diff --git a/doc/api/resources/item_add-ons.rst b/doc/api/resources/item_add-ons.rst
index b2494e132..2e3078eb8 100644
--- a/doc/api/resources/item_add-ons.rst
+++ b/doc/api/resources/item_add-ons.rst
@@ -24,6 +24,7 @@ addon_category                        integer                    Internal ID of
 min_count                             integer                    The minimal number of add-ons that need to be chosen.
 max_count                             integer                    The maximal number of add-ons that can be chosen.
 position                              integer                    An integer, used for sorting
+multi_allowed                         boolean                    Adding the same item multiple times is allowed
 price_included                        boolean                    Adding this add-on to the item is free
 ===================================== ========================== =======================================================
 
@@ -65,6 +66,7 @@ Endpoints
             "min_count": 0,
             "max_count": 10,
             "position": 0,
+            "multi_allowed": false,
             "price_included": true
           },
           {
@@ -73,6 +75,7 @@ Endpoints
             "min_count": 0,
             "max_count": 10,
             "position": 1,
+            "multi_allowed": false,
             "price_included": true
           }
         ]
@@ -112,6 +115,7 @@ Endpoints
         "min_count": 0,
         "max_count": 10,
         "position": 1,
+        "multi_allowed": false,
         "price_included": true
       }
 
@@ -141,6 +145,7 @@ Endpoints
         "min_count": 0,
         "max_count": 10,
         "position": 1,
+        "multi_allowed": false,
         "price_included": true
       }
 
@@ -158,6 +163,7 @@ Endpoints
         "min_count": 0,
         "max_count": 10,
         "position": 1,
+        "multi_allowed": false,
         "price_included": true
       }
 
@@ -206,6 +212,7 @@ Endpoints
         "min_count": 0,
         "max_count": 10,
         "position": 1,
+        "multi_allowed": false,
         "price_included": true
       }
 
diff --git a/doc/api/resources/items.rst b/doc/api/resources/items.rst
index 8b9cfbad7..1ee80386b 100644
--- a/doc/api/resources/items.rst
+++ b/doc/api/resources/items.rst
@@ -104,6 +104,7 @@ addons                                list of objects            Definition of a
 ├ min_count                           integer                    The minimal number of add-ons that need to be chosen.
 ├ max_count                           integer                    The maximal number of add-ons that can be chosen.
 ├ position                            integer                    An integer, used for sorting
+├ multi_allowed                       boolean                    Adding the same item multiple times is allowed
 └ price_included                      boolean                    Adding this add-on to the item is free
 bundles                               list of objects            Definition of bundles that are included in this item.
                                                                  Only writable during creation,
@@ -159,6 +160,10 @@ meta_data                             object                     Values set for
 
    The attribute ``meta_data`` has been added.
 
+.. versionchanged:: 3.10
+
+   The attribute ``multi_allowed`` has been added to ``addons``.
+
 Notes
 -----
 
diff --git a/src/pretix/api/serializers/item.py b/src/pretix/api/serializers/item.py
index 8924a0296..f48f12031 100644
--- a/src/pretix/api/serializers/item.py
+++ b/src/pretix/api/serializers/item.py
@@ -45,7 +45,7 @@ class InlineItemAddOnSerializer(serializers.ModelSerializer):
     class Meta:
         model = ItemAddOn
         fields = ('addon_category', 'min_count', 'max_count',
-                  'position', 'price_included')
+                  'position', 'price_included', 'multi_allowed')
 
 
 class ItemBundleSerializer(serializers.ModelSerializer):
@@ -77,7 +77,7 @@ class ItemAddOnSerializer(serializers.ModelSerializer):
     class Meta:
         model = ItemAddOn
         fields = ('id', 'addon_category', 'min_count', 'max_count',
-                  'position', 'price_included')
+                  'position', 'price_included', 'multi_allowed')
 
     def validate(self, data):
         data = super().validate(data)
diff --git a/src/pretix/base/migrations/0157_auto_20200712_0932.py b/src/pretix/base/migrations/0157_auto_20200712_0932.py
new file mode 100644
index 000000000..adeecee28
--- /dev/null
+++ b/src/pretix/base/migrations/0157_auto_20200712_0932.py
@@ -0,0 +1,20 @@
+# Generated by Django 3.0.6 on 2020-07-12 09:32
+
+from django.db import migrations, models
+
+import pretix.helpers.countries
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0156_cartposition_override_tax_rate'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='itemaddon',
+            name='multi_allowed',
+            field=models.BooleanField(default=False),
+        ),
+    ]
diff --git a/src/pretix/base/models/items.py b/src/pretix/base/models/items.py
index b76573c4e..bbb67525a 100644
--- a/src/pretix/base/models/items.py
+++ b/src/pretix/base/models/items.py
@@ -840,6 +840,10 @@ class ItemAddOn(models.Model):
         help_text=_('If selected, adding add-ons to this ticket is free, even if the add-ons would normally cost '
                     'money individually.')
     )
+    multi_allowed = models.BooleanField(
+        default=False,
+        verbose_name=_('Allow the same product to be selected multiple times'),
+    )
     position = models.PositiveIntegerField(
         default=0,
         verbose_name=_("Position")
diff --git a/src/pretix/base/services/cart.py b/src/pretix/base/services/cart.py
index 87bdb641c..8634a8d29 100644
--- a/src/pretix/base/services/cart.py
+++ b/src/pretix/base/services/cart.py
@@ -96,6 +96,7 @@ error_messages = {
     'addon_max_count': _('You can select at most %(max)s add-ons from the category %(cat)s for the product %(base)s.'),
     'addon_min_count': _('You need to select at least %(min)s add-ons from the category %(cat)s for the '
                          'product %(base)s.'),
+    'addon_no_multi': _('You can select every add-ons from the category %(cat)s for the product %(base)s at most once.'),
     'addon_only': _('One of the products you selected can only be bought as an add-on to another project.'),
     'bundled_only': _('One of the products you selected can only be bought part of a bundle.'),
     'seat_required': _('You need to select a specific seat.'),
@@ -605,9 +606,9 @@ class CartManager:
         )
 
         # Prepare various containers to hold data later
-        current_addons = defaultdict(dict)  # CartPos -> currently attached add-ons
-        input_addons = defaultdict(set)  # CartPos -> add-ons according to input
-        selected_addons = defaultdict(set)  # CartPos -> final desired set of add-ons
+        current_addons = defaultdict(lambda: defaultdict(list))  # CartPos -> currently attached add-ons
+        input_addons = defaultdict(Counter)  # CartPos -> final desired set of add-ons
+        selected_addons = defaultdict(Counter)  # CartPos, ItemAddOn -> final desired set of add-ons
         cpcache = {}  # CartPos.pk -> CartPos
         quota_diff = Counter()  # Quota -> Number of usages
         operations = []
@@ -624,11 +625,9 @@ class CartManager:
             available_categories[cp.pk] = {iao.addon_category_id for iao in cp.item.addons.all()}
             price_included[cp.pk] = {iao.addon_category_id: iao.price_included for iao in cp.item.addons.all()}
             cpcache[cp.pk] = cp
-            current_addons[cp] = {
-                (a.item_id, a.variation_id): a
-                for a in cp.addons.all()
-                if not a.is_bundled
-            }
+            for a in cp.addons.all():
+                if not a.is_bundled:
+                    current_addons[cp][a.item_id, a.variation_id].append(a)
 
         # Create operations, perform various checks
         for a in addons:
@@ -655,25 +654,31 @@ class CartManager:
             if not quotas:
                 raise CartError(error_messages['unavailable'])
 
-            # Every item can be attached to very CartPosition at most once
-            if a['item'] in ([_a[0] for _a in input_addons[cp.id]]):
+            if (a['item'], a['variation']) in input_addons[cp.id]:
                 raise CartError(error_messages['addon_duplicate_item'])
 
-            input_addons[cp.id].add((a['item'], a['variation']))
-            selected_addons[cp.id, item.category_id].add((a['item'], a['variation']))
+            input_addons[cp.id][a['item'], a['variation']] = a.get('count', 1)
+            selected_addons[cp.id, item.category_id][a['item'], a['variation']] = a.get('count', 1)
 
-            if (a['item'], a['variation']) not in current_addons[cp]:
+            if price_included[cp.pk].get(item.category_id):
+                price = TAXED_ZERO
+            else:
+                price = self._get_price(item, variation, None, a.get('price'), cp.subevent)
+
+            # Fix positions with wrong price (TODO: happens out-of-cartmanager-transaction and therefore a little hacky)
+            for ca in current_addons[cp][a['item'], a['variation']]:
+                if ca.price != price.gross:
+                    ca.price = price.gross
+                    ca.save(update_fields=['price'])
+
+            if a.get('count', 1) > len(current_addons[cp][a['item'], a['variation']]):
                 # This add-on is new, add it to the cart
                 for quota in quotas:
-                    quota_diff[quota] += 1
-
-                if price_included[cp.pk].get(item.category_id):
-                    price = TAXED_ZERO
-                else:
-                    price = self._get_price(item, variation, None, None, cp.subevent)
+                    quota_diff[quota] += a.get('count', 1) - len(current_addons[cp][a['item'], a['variation']])
 
                 op = self.AddOperation(
-                    count=1, item=item, variation=variation, price=price, voucher=None, quotas=quotas,
+                    count=a.get('count', 1) - len(current_addons[cp][a['item'], a['variation']]),
+                    item=item, variation=variation, price=price, voucher=None, quotas=quotas,
                     addon_to=cp, subevent=cp.subevent, includes_tax=bool(price.rate), bundled=[], seat=None,
                     price_before_voucher=None
                 )
@@ -685,7 +690,10 @@ class CartManager:
             item = cp.item
             for iao in item.addons.all():
                 selected = selected_addons[cp.id, iao.addon_category_id]
-                if len(selected) > iao.max_count:
+                n_per_i = Counter()
+                for (i, v), c in selected.items():
+                    n_per_i[i] += c
+                if sum(selected.values()) > iao.max_count:
                     # TODO: Proper i18n
                     # TODO: Proper pluralization
                     raise CartError(
@@ -696,7 +704,7 @@ class CartManager:
                             'cat': str(iao.addon_category.name),
                         }
                     )
-                elif len(selected) < iao.min_count:
+                elif sum(selected.values()) < iao.min_count:
                     # TODO: Proper i18n
                     # TODO: Proper pluralization
                     raise CartError(
@@ -707,28 +715,39 @@ class CartManager:
                             'cat': str(iao.addon_category.name),
                         }
                     )
+                elif any(v > 1 for v in n_per_i.values()) and not iao.multi_allowed:
+                    raise CartError(
+                        error_messages['addon_no_multi'],
+                        {
+                            'base': str(item.name),
+                            'cat': str(iao.addon_category.name),
+                        }
+                    )
                 validate_cart_addons.send(
                     sender=self.event,
                     addons={
-                        (self._items_cache[s[0]], self._variations_cache[s[1]] if s[1] else None)
-                        for s in selected
+                        (self._items_cache[s[0]], self._variations_cache[s[1]] if s[1] else None): c
+                        for s, c in selected.items() if c > 0
                     },
                     base_position=cp,
                     iao=iao
                 )
 
         # Detect removed add-ons and create RemoveOperations
-        for cp, al in current_addons.items():
+        for cp, al in list(current_addons.items()):
             for k, v in al.items():
-                if k not in input_addons[cp.id]:
-                    if v.expires > self.now_dt:
-                        quotas = list(v.quotas)
+                input_num = input_addons[cp.id].get(k, 0)
+                current_num = len(current_addons[cp].get(k, []))
+                if input_num < current_num:
+                    for a in current_addons[cp][k][:current_num - input_num]:
+                        if a.expires > self.now_dt:
+                            quotas = list(a.quotas)
 
-                        for quota in quotas:
-                            quota_diff[quota] -= 1
+                            for quota in quotas:
+                                quota_diff[quota] -= 1
 
-                    op = self.RemoveOperation(position=v)
-                    operations.append(op)
+                        op = self.RemoveOperation(position=a)
+                        operations.append(op)
 
         self._quota_diff.update(quota_diff)
         self._operations += operations
diff --git a/src/pretix/base/signals.py b/src/pretix/base/signals.py
index 858789b27..9ae3d2697 100644
--- a/src/pretix/base/signals.py
+++ b/src/pretix/base/signals.py
@@ -309,7 +309,7 @@ validate_cart_addons = EventPluginSignal(
 """
 This signal is sent when a user tries to select a combination of addons. In contrast to
  ``validate_cart``, this is executed before the cart is actually modified. You are passed
-an argument ``addons`` containing a set of ``(item, variation or None)`` tuples as well
+an argument ``addons`` containing a dict of ``(item, variation or None) → count`` tuples as well
 as the ``ItemAddOn`` object as the argument ``iao`` and the base cart position as
 ``base_position``.
 The response of receivers will be ignored, but you can raise a CartError with an
diff --git a/src/pretix/control/forms/item.py b/src/pretix/control/forms/item.py
index fecf1b42f..82b3da9cd 100644
--- a/src/pretix/control/forms/item.py
+++ b/src/pretix/control/forms/item.py
@@ -661,7 +661,8 @@ class ItemAddOnForm(I18nModelForm):
             'addon_category',
             'min_count',
             'max_count',
-            'price_included'
+            'price_included',
+            'multi_allowed',
         ]
         help_texts = {
             'min_count': _('Be aware that setting a minimal number makes it impossible to buy this product if all '
diff --git a/src/pretix/control/templates/pretixcontrol/item/include_addons.html b/src/pretix/control/templates/pretixcontrol/item/include_addons.html
index 9afa0bcef..9cf9df065 100644
--- a/src/pretix/control/templates/pretixcontrol/item/include_addons.html
+++ b/src/pretix/control/templates/pretixcontrol/item/include_addons.html
@@ -43,6 +43,7 @@
                     {% bootstrap_field form.addon_category layout="control" %}
                     {% bootstrap_field form.min_count layout="control" %}
                     {% bootstrap_field form.max_count layout="control" %}
+                    {% bootstrap_field form.multi_allowed layout="control" %}
                     {% bootstrap_field form.price_included layout="control" %}
                 </div>
             </div>
@@ -75,6 +76,7 @@
                     {% bootstrap_field formset.empty_form.addon_category layout="control" %}
                     {% bootstrap_field formset.empty_form.min_count layout="control" %}
                     {% bootstrap_field formset.empty_form.max_count layout="control" %}
+                    {% bootstrap_field formset.empty_form.multi_allowed layout="control" %}
                     {% bootstrap_field formset.empty_form.price_included layout="control" %}
                 </div>
             </div>
diff --git a/src/pretix/presale/checkoutflow.py b/src/pretix/presale/checkoutflow.py
index 720296636..5d77533cf 100644
--- a/src/pretix/presale/checkoutflow.py
+++ b/src/pretix/presale/checkoutflow.py
@@ -1,4 +1,5 @@
 import inspect
+from collections import defaultdict
 from decimal import Decimal
 
 from django.conf import settings
@@ -17,15 +18,17 @@ from django_scopes import scopes_disabled
 
 from pretix.base.models import Order
 from pretix.base.models.orders import InvoiceAddress, OrderPayment
+from pretix.base.models.tax import TaxedPrice
 from pretix.base.services.cart import (
-    get_fees, set_cart_addons, update_tax_rates,
+    CartError, error_messages, get_fees, set_cart_addons, update_tax_rates,
 )
 from pretix.base.services.orders import perform_order
+from pretix.base.signals import validate_cart_addons
 from pretix.base.templatetags.rich_text import rich_text_snippet
 from pretix.base.views.tasks import AsyncAction
 from pretix.multidomain.urlreverse import eventreverse
 from pretix.presale.forms.checkout import (
-    AddOnsForm, ContactForm, InvoiceAddressForm, InvoiceNameForm,
+    ContactForm, InvoiceAddressForm, InvoiceNameForm,
 )
 from pretix.presale.signals import (
     checkout_all_optional, checkout_confirm_messages, checkout_flow_steps,
@@ -37,6 +40,7 @@ from pretix.presale.views import (
 from pretix.presale.views.cart import (
     cart_session, create_empty_cart_id, get_or_create_cart_id,
 )
+from pretix.presale.views.event import get_grouped_items
 from pretix.presale.views.questions import QuestionsViewMixin
 
 
@@ -224,39 +228,79 @@ class AddOnsStep(CartMixin, AsyncAction, TemplateFlowStep):
         for cartpos in get_cart(self.request).filter(addon_to__isnull=True).prefetch_related(
             'item__addons', 'item__addons__addon_category', 'addons', 'addons__variation',
         ).order_by('pk'):
-            current_addon_products = {
-                a.item_id: a.variation_id for a in cartpos.addons.all() if not a.is_bundled
-            }
             formsetentry = {
                 'cartpos': cartpos,
                 'item': cartpos.item,
                 'variation': cartpos.variation,
                 'categories': []
             }
-            for iao in cartpos.item.addons.all():
-                category = {
-                    'category': iao.addon_category,
-                    'min_count': iao.min_count,
-                    'max_count': iao.max_count,
-                    'form': AddOnsForm(
-                        event=self.request.event,
-                        prefix='{}_{}'.format(cartpos.pk, iao.addon_category.pk),
-                        base_position=cartpos,
-                        iao=iao,
-                        price_included=iao.price_included,
-                        initial=current_addon_products,
-                        data=(self.request.POST if self.request.method == 'POST' else None),
-                        quota_cache=quota_cache,
-                        item_cache=item_cache,
-                        subevent=cartpos.subevent,
-                        sales_channel=self.request.sales_channel.identifier
-                    )
-                }
-
-                if len(category['form'].fields) > 0:
-                    formsetentry['categories'].append(category)
-
             formset.append(formsetentry)
+
+            current_addon_products = defaultdict(list)
+            for a in cartpos.addons.all():
+                if not a.is_bundled:
+                    current_addon_products[a.item_id, a.variation_id].append(a)
+
+            for iao in cartpos.item.addons.all():
+                ckey = '{}-{}'.format(cartpos.subevent.pk if cartpos.subevent else 0, iao.addon_category.pk)
+
+                if ckey not in item_cache:
+                    # Get all items to possibly show
+                    items, _btn = get_grouped_items(
+                        self.request.event,
+                        subevent=cartpos.subevent,
+                        voucher=None,
+                        channel=self.request.sales_channel.identifier,
+                        base_qs=iao.addon_category.items,
+                        allow_addons=True,
+                        quota_cache=quota_cache
+                    )
+                    item_cache[ckey] = items
+                else:
+                    items = item_cache[ckey]
+
+                for i in items:
+                    i.allow_waitinglist = False
+
+                    if i.has_variations:
+                        for v in i.available_variations:
+                            v.initial = len(current_addon_products[i.pk, v.pk])
+                            if v.initial and i.free_price:
+                                a = current_addon_products[i.pk, v.pk][0]
+                                v.initial_price = TaxedPrice(
+                                    net=a.price - a.tax_value,
+                                    gross=a.price,
+                                    tax=a.tax_value,
+                                    name=a.item.tax_rule.name,
+                                    rate=a.tax_rate,
+                                )
+                            else:
+                                v.initial_price = v.display_price
+                        i.expand = any(v.initial for v in i.available_variations)
+                    else:
+                        i.initial = len(current_addon_products[i.pk, None])
+                        if i.initial and i.free_price:
+                            a = current_addon_products[i.pk, None][0]
+                            i.initial_price = TaxedPrice(
+                                net=a.price - a.tax_value,
+                                gross=a.price,
+                                tax=a.tax_value,
+                                name=a.item.tax_rule.name,
+                                rate=a.tax_rate,
+                            )
+                        else:
+                            i.initial_price = i.display_price
+
+                if items:
+                    formsetentry['categories'].append({
+                        'category': iao.addon_category,
+                        'price_included': iao.price_included,
+                        'multi_allowed': iao.multi_allowed,
+                        'min_count': iao.min_count,
+                        'max_count': iao.max_count,
+                        'iao': iao,
+                        'items': items
+                    })
         return formset
 
     def get_context_data(self, **kwargs):
@@ -274,37 +318,89 @@ class AddOnsStep(CartMixin, AsyncAction, TemplateFlowStep):
     def get_error_url(self):
         return self.get_step_url(self.request)
 
-    def get(self, request):
+    def get(self, request, **kwargs):
         self.request = request
         if 'async_id' in request.GET and settings.HAS_CELERY:
             return self.get_result(request)
         return TemplateFlowStep.get(self, request)
 
+    def _clean_category(self, form, category):
+        selected = {}
+        for i in category['items']:
+            if i.has_variations:
+                for v in i.available_variations:
+                    val = int(self.request.POST.get(f'cp_{form["cartpos"].pk}_variation_{i.pk}_{v.pk}') or '0')
+                    price = self.request.POST.get(f'cp_{form["cartpos"].pk}_variation_{i.pk}_{v.pk}_price') or '0'
+                    if val:
+                        selected[i, v] = val, price
+            else:
+                val = int(self.request.POST.get(f'cp_{form["cartpos"].pk}_item_{i.pk}') or '0')
+                price = self.request.POST.get(f'cp_{form["cartpos"].pk}_item_{i.pk}_price') or '0'
+                if val:
+                    selected[i, None] = val, price
+
+        if sum(a[0] for a in selected.values()) > category['max_count']:
+            # TODO: Proper pluralization
+            raise ValidationError(
+                _(error_messages['addon_max_count']),
+                'addon_max_count',
+                {
+                    'base': str(form['item'].name),
+                    'max': category['max_count'],
+                    'cat': str(category['category'].name),
+                }
+            )
+        elif sum(a[0] for a in selected.values()) < category['min_count']:
+            # TODO: Proper pluralization
+            raise ValidationError(
+                _(error_messages['addon_min_count']),
+                'addon_min_count',
+                {
+                    'base': str(form['item'].name),
+                    'min': category['min_count'],
+                    'cat': str(category['category'].name),
+                }
+            )
+        elif any(sum(v[0] for k, v in selected.items() if k[0] == i) > 1 for i in category['items']) and not category['multi_allowed']:
+            raise ValidationError(
+                _(error_messages['addon_no_multi']),
+                'addon_no_multi',
+                {
+                    'base': str(form['item'].name),
+                    'cat': str(category['category'].name),
+                }
+            )
+        try:
+            validate_cart_addons.send(
+                sender=self.event,
+                addons={k: v[0] for k, v in selected.items()},
+                base_position=form["cartpos"],
+                iao=category['iao']
+            )
+        except CartError as e:
+            raise ValidationError(str(e))
+
+        return selected
+
     def post(self, request, *args, **kwargs):
         self.request = request
-        is_valid = True
         data = []
         for f in self.forms:
             for c in f['categories']:
-                is_valid = is_valid and c['form'].is_valid()
-                if c['form'].is_valid():
-                    for k, v in c['form'].cleaned_data.items():
-                        itemid = int(k[5:])
-                        if v is True:
-                            data.append({
-                                'addon_to': f['cartpos'].pk,
-                                'item': itemid,
-                                'variation': None
-                            })
-                        elif v:
-                            data.append({
-                                'addon_to': f['cartpos'].pk,
-                                'item': itemid,
-                                'variation': int(v)
-                            })
+                try:
+                    selected = self._clean_category(f, c)
+                except ValidationError as e:
+                    messages.error(request, e.message % e.params if e.params else e.message)
+                    return self.get(request, *args, **kwargs)
 
-        if not is_valid:
-            return self.get(request, *args, **kwargs)
+                for (i, v), (c, price) in selected.items():
+                    data.append({
+                        'addon_to': f['cartpos'].pk,
+                        'item': i.pk,
+                        'variation': v.pk if v else None,
+                        'count': c,
+                        'price': price,
+                    })
 
         return self.do(self.request.event.id, data, get_or_create_cart_id(self.request),
                        invoice_address=self.invoice_address.pk, locale=get_language(),
diff --git a/src/pretix/presale/forms/checkout.py b/src/pretix/presale/forms/checkout.py
index 9dc533de0..23600c944 100644
--- a/src/pretix/presale/forms/checkout.py
+++ b/src/pretix/presale/forms/checkout.py
@@ -2,24 +2,13 @@ from itertools import chain
 
 from django import forms
 from django.core.exceptions import ValidationError
-from django.db.models import Count, Prefetch
 from django.utils.encoding import force_str
-from django.utils.formats import number_format
-from django.utils.html import escape
-from django.utils.safestring import mark_safe
 from django.utils.translation import gettext_lazy as _
 
 from pretix.base.forms.questions import (
     BaseInvoiceAddressForm, BaseQuestionsForm,
 )
-from pretix.base.models import ItemVariation, Quota
-from pretix.base.models.tax import TAXED_ZERO
-from pretix.base.services.cart import CartError, error_messages
-from pretix.base.signals import validate_cart_addons
-from pretix.base.templatetags.money import money_filter
-from pretix.base.templatetags.rich_text import rich_text
 from pretix.base.validators import EmailBanlistValidator
-from pretix.helpers.templatetags.thumb import thumb
 from pretix.presale.signals import contact_form_fields
 
 
@@ -126,230 +115,3 @@ class AddOnVariationField(forms.ChoiceField):
             if value == k or text_value == force_str(k):
                 return True
         return False
-
-
-class AddOnsForm(forms.Form):
-    """
-    This form class is responsible for selecting add-ons to a product in the cart.
-    """
-
-    def _label(self, event, item_or_variation, avail, override_price=None, initial=False):
-        if isinstance(item_or_variation, ItemVariation):
-            variation = item_or_variation
-            item = item_or_variation.item
-            price = variation.price
-            label = variation.value
-        else:
-            item = item_or_variation
-            price = item.default_price
-            label = item.name
-
-        if override_price:
-            price = override_price
-
-        if self.price_included:
-            price = TAXED_ZERO
-        else:
-            price = item.tax(price)
-
-        if not price.gross:
-            n = '{name}'.format(
-                name=label
-            )
-        elif not price.rate:
-            n = _('{name} (+ {price})').format(
-                name=label, price=money_filter(price.gross, event.currency)
-            )
-        elif event.settings.display_net_prices:
-            n = _('{name} (+ {price} plus {taxes}% {taxname})').format(
-                name=label, price=money_filter(price.net, event.currency),
-                taxes=number_format(price.rate), taxname=price.name
-            )
-        else:
-            n = _('{name} (+ {price} incl. {taxes}% {taxname})').format(
-                name=label, price=money_filter(price.gross, event.currency),
-                taxes=number_format(price.rate), taxname=price.name
-            )
-
-        if not initial:
-            if avail[0] < Quota.AVAILABILITY_RESERVED:
-                n += ' – {}'.format(_('SOLD OUT'))
-            elif avail[0] < Quota.AVAILABILITY_OK:
-                n += ' – {}'.format(_('Currently unavailable'))
-            else:
-                if avail[1] is not None and item.do_show_quota_left:
-                    n += ' – {}'.format(_('%(num)s currently available') % {'num': avail[1]})
-
-        if not isinstance(item_or_variation, ItemVariation) and item.picture:
-            n = escape(n)
-            n += '<br>'
-            n += '<a href="{}" class="productpicture" data-title="{}" data-lightbox={}>'.format(
-                item.picture.url, escape(escape(item.name)), item.id
-            )
-            n += '<img src="{}" alt="{}">'.format(
-                thumb(item.picture, '60x60^'),
-                escape(item.name)
-            )
-            n += '</a>'
-            n = mark_safe(n)
-        return n
-
-    def __init__(self, *args, **kwargs):
-        """
-        Takes additional keyword arguments:
-
-        :param iao: The ItemAddOn object
-        :param event: The event this belongs to
-        :param subevent: The event the parent cart position belongs to
-        :param initial: The current set of add-ons
-        :param quota_cache: A shared dictionary for quota caching
-        :param item_cache: A shared dictionary for item/category caching
-        """
-        self.iao = kwargs.pop('iao')
-        category = self.iao.addon_category
-        self.event = kwargs.pop('event')
-        subevent = kwargs.pop('subevent')
-        current_addons = kwargs.pop('initial')
-        quota_cache = kwargs.pop('quota_cache')
-        item_cache = kwargs.pop('item_cache')
-        self.price_included = kwargs.pop('price_included')
-        self.sales_channel = kwargs.pop('sales_channel')
-        self.base_position = kwargs.pop('base_position')
-
-        super().__init__(*args, **kwargs)
-
-        if subevent:
-            item_price_override = subevent.item_price_overrides
-            var_price_override = subevent.var_price_overrides
-        else:
-            item_price_override = {}
-            var_price_override = {}
-
-        ckey = '{}-{}'.format(subevent.pk if subevent else 0, category.pk)
-        if ckey not in item_cache:
-            # Get all items to possibly show
-            items = category.items.filter_available(
-                channel=self.sales_channel,
-                allow_addons=True
-            ).select_related('tax_rule').prefetch_related(
-                Prefetch('quotas',
-                         to_attr='_subevent_quotas',
-                         queryset=self.event.quotas.filter(subevent=subevent)),
-                Prefetch('variations', to_attr='available_variations',
-                         queryset=ItemVariation.objects.filter(active=True, quotas__isnull=False).prefetch_related(
-                             Prefetch('quotas',
-                                      to_attr='_subevent_quotas',
-                                      queryset=self.event.quotas.filter(subevent=subevent))
-                         ).distinct()),
-                'event'
-            ).annotate(
-                quotac=Count('quotas'),
-                has_variations=Count('variations')
-            ).filter(
-                quotac__gt=0
-            ).order_by('category__position', 'category_id', 'position', 'name')
-            item_cache[ckey] = items
-        else:
-            items = item_cache[ckey]
-
-        self.vars_cache = {}
-
-        for i in items:
-            if i.hidden_if_available:
-                q = i.hidden_if_available.availability(_cache=quota_cache)
-                if q[0] == Quota.AVAILABILITY_OK:
-                    continue
-
-            if i.has_variations:
-                choices = [('', _('no selection'), '')]
-                for v in i.available_variations:
-                    cached_availability = v.check_quotas(subevent=subevent, _cache=quota_cache)
-                    if self.event.settings.hide_sold_out and cached_availability[0] < Quota.AVAILABILITY_RESERVED:
-                        continue
-
-                    if v._subevent_quotas:
-                        self.vars_cache[v.pk] = v
-                        choices.append(
-                            (v.pk,
-                             self._label(self.event, v, cached_availability,
-                                         override_price=var_price_override.get(v.pk),
-                                         initial=current_addons.get(i.pk) == v.pk),
-                             v.description)
-                        )
-
-                n = i.name
-                if i.picture:
-                    n = escape(n)
-                    n += '<br>'
-                    n += '<a href="{}" class="productpicture" data-title="{}" data-lightbox="{}">'.format(
-                        i.picture.url, escape(escape(i.name)), i.id
-                    )
-                    n += '<img src="{}" alt="{}">'.format(
-                        thumb(i.picture, '60x60^'),
-                        escape(i.name)
-                    )
-                    n += '</a>'
-                    n = mark_safe(n)
-                field = AddOnVariationField(
-                    choices=choices,
-                    label=n,
-                    required=False,
-                    widget=AddOnRadioSelect,
-                    help_text=rich_text(str(i.description)),
-                    initial=current_addons.get(i.pk),
-                )
-                field.item = i
-                if len(choices) > 1:
-                    self.fields['item_%s' % i.pk] = field
-            else:
-                if not i._subevent_quotas:
-                    continue
-                cached_availability = i.check_quotas(subevent=subevent, _cache=quota_cache)
-                if self.event.settings.hide_sold_out and cached_availability[0] < Quota.AVAILABILITY_RESERVED:
-                    continue
-                field = forms.BooleanField(
-                    label=self._label(self.event, i, cached_availability,
-                                      override_price=item_price_override.get(i.pk),
-                                      initial=i.pk in current_addons),
-                    required=False,
-                    initial=i.pk in current_addons,
-                    help_text=rich_text(str(i.description)),
-                )
-                field.item = i
-                self.fields['item_%s' % i.pk] = field
-
-    def clean(self):
-        data = super().clean()
-        selected = set()
-        for k, v in data.items():
-            if v is True:
-                selected.add((self.fields[k].item, None))
-            elif v:
-                selected.add((self.fields[k].item, self.vars_cache.get(int(v))))
-        if len(selected) > self.iao.max_count:
-            # TODO: Proper pluralization
-            raise ValidationError(
-                _(error_messages['addon_max_count']),
-                'addon_max_count',
-                {
-                    'base': str(self.iao.base_item.name),
-                    'max': self.iao.max_count,
-                    'cat': str(self.iao.addon_category.name),
-                }
-            )
-        elif len(selected) < self.iao.min_count:
-            # TODO: Proper pluralization
-            raise ValidationError(
-                _(error_messages['addon_min_count']),
-                'addon_min_count',
-                {
-                    'base': str(self.iao.base_item.name),
-                    'min': self.iao.min_count,
-                    'cat': str(self.iao.addon_category.name),
-                }
-            )
-        try:
-            validate_cart_addons.send(sender=self.event, addons=selected, base_position=self.base_position,
-                                      iao=self.iao)
-        except CartError as e:
-            raise ValidationError(str(e))
diff --git a/src/pretix/presale/templates/pretixpresale/event/checkout_addons.html b/src/pretix/presale/templates/pretixpresale/event/checkout_addons.html
index d1d1b123f..2e7b43acd 100644
--- a/src/pretix/presale/templates/pretixpresale/event/checkout_addons.html
+++ b/src/pretix/presale/templates/pretixpresale/event/checkout_addons.html
@@ -2,6 +2,9 @@
 {% load i18n %}
 {% load bootstrap3 %}
 {% load rich_text %}
+{% load l10n %}
+{% load money %}
+{% load thumb %}
 {% block inner %}
     <p>
         {% trans "For some of the products in your cart, you can choose additional options before you continue." %}
@@ -9,7 +12,7 @@
     <form class="form-horizontal" method="post" data-asynctask
             data-asynctask-headline="{% trans "We're now trying to book these add-ons for you!" %}">
         {% csrf_token %}
-        <div class="panel-group" id="questions_group">
+        <div class="panel-group addons" id="questions_group">
             {% for form in forms %}
                 <details class="panel panel-default" open>
                     <summary class="panel-heading">
@@ -45,7 +48,11 @@
                                             {% plural %}
                                                 You need to choose {{ min_count }} options from this category.
                                             {% endblocktrans %}
-                                        {% elif c.min_count == 0 and c.max_count >= c.form.fields|length %}
+                                        {% elif c.min_count == 0 and c.max_count >= c.items|length and not c.multi_allowed %}
+                                        {% elif c.min_count == 0 %}
+                                            {% blocktrans trimmed with max_count=c.max_count %}
+                                                You can choose up to {{ max_count }} options from this category.
+                                            {% endblocktrans %}
                                         {% else %}
                                             {% blocktrans trimmed with min_count=c.min_count max_count=c.max_count %}
                                                 You can choose between {{ min_count }} and {{ max_count }} options from
@@ -53,7 +60,265 @@
                                             {% endblocktrans %}
                                         {% endif %}
                                     </p>
-                                    {% bootstrap_form c.form layout="horizontal" %}
+                                    {% for item in c.items %}
+                                        {% if item.has_variations %}
+                                            <details class="item-with-variations" {% if event.settings.show_variations_expanded or item.expand %}open{% endif %}>
+                                                <summary class="row-fluid product-row headline">
+                                                    <div class="col-md-8 col-xs-12">
+                                                        {% if item.picture %}
+                                                            <a href="{{ item.picture.url }}" class="productpicture"
+                                                               data-title="{{ item.name|force_escape|force_escape }}"
+                                                                    {# Yes, double-escape to prevent XSS in lightbox #}
+                                                               data-lightbox="{{ item.id }}">
+                                                                <img src="{{ item.picture|thumb:'60x60^' }}"
+                                                                     alt="{{ item.name }}"/>
+                                                            </a>
+                                                        {% endif %}
+                                                        <div class="product-description {% if item.picture %}with-picture{% endif %}">
+                                                            <h4>
+                                                                <a href="#" data-toggle="variations">
+                                                                    {{ item.name }}
+                                                                </a>
+                                                            </h4>
+                                                            {% if item.description %}
+                                                                <div class="product-description">
+                                                                    {{ item.description|localize|rich_text }}
+                                                                </div>
+                                                            {% endif %}
+                                                            {% if item.min_per_order and item.min_per_order > 1 %}
+                                                                <p>
+                                                                    <small>
+                                                                        {% blocktrans trimmed with num=item.min_per_order %}
+                                                                            minimum amount to order: {{ num }}
+                                                                        {% endblocktrans %}
+                                                                    </small>
+                                                                </p>
+                                                            {% endif %}
+                                                        </div>
+                                                    </div>
+                                                    <div class="col-md-2 col-xs-6 price">
+                                                        {% if c.price_included %}
+                                                        {% elif item.free_price %}
+                                                            {% blocktrans trimmed with price=item.min_price|money:event.currency %}
+                                                                from {{ price }}
+                                                            {% endblocktrans %}
+                                                        {% elif item.min_price != item.max_price %}
+                                                            {{ item.min_price|money:event.currency  }} – {{ item.max_price|money:event.currency  }}
+                                                        {% elif not item.min_price and not item.max_price %}
+                                                        {% else %}
+                                                            {{ item.min_price|money:event.currency }}
+                                                        {% endif %}
+                                                    </div>
+                                                    <div class="col-md-2 col-xs-6 availability-box">
+                                                        {% if not event.settings.show_variations_expanded %}
+                                                            <a href="#" data-toggle="variations" class="js-only">
+                                                                {% trans "Show variants" %}
+                                                            </a>
+                                                        {% endif %}
+                                                    </div>
+                                                    <div class="clearfix"></div>
+                                                </summary>
+                                                <div class="variations {% if not event.settings.show_variations_expanded %}variations-collapsed{% endif %}">
+                                                    {% for var in item.available_variations %}
+                                                        <div class="row-fluid product-row variation">
+                                                            <div class="col-md-8 col-xs-12">
+                                                                <h5>
+                                                                    <label for="cp_{{ form.cartpos.pk }}_variation_{{ item.pk }}_{{ var.pk }}">
+                                                                        {{ var }}
+                                                                    </label>
+                                                                </h5>
+                                                                {% if var.description %}
+                                                                    <div class="variation-description">
+                                                                        {{ var.description|localize|rich_text }}
+                                                                    </div>
+                                                                {% endif %}
+                                                                {% if item.do_show_quota_left %}
+                                                                    {% include "pretixpresale/event/fragment_quota_left.html" with avail=var.cached_availability %}
+                                                                {% endif %}
+                                                            </div>
+                                                            <div class="col-md-2 col-xs-6 price">
+                                                                {% if not c.price_included %}
+                                                                    {% if var.original_price %}
+                                                                        {% if event.settings.display_net_prices %}
+                                                                            <del>{{ var.original_price.net|money:event.currency }}</del>
+                                                                        {% else %}
+                                                                            <del>{{ var.original_price.gross|money:event.currency }}</del>
+                                                                        {% endif %}
+                                                                        <ins>
+                                                                    {% endif %}
+                                                                    {% if item.free_price %}
+                                                                        <div class="input-group input-group-price">
+                                                                            <span class="input-group-addon">{{ event.currency }}</span>
+                                                                            <input type="number" class="form-control input-item-price"
+                                                                                    placeholder="0"
+                                                                                    min="{% if event.settings.display_net_prices %}{{ var.display_price.net|money_numberfield:event.currency }}{% else %}{{ var.display_price.gross|money_numberfield:event.currency }}{% endif %}"
+                                                                                    name="cp_{{ form.cartpos.pk }}_variation_{{ item.id }}_{{ var.id }}_price"
+                                                                                    title="{% blocktrans trimmed with item=var.value %}Modify price for {{ item }}{% endblocktrans %}"
+                                                                                    step="any"
+                                                                                    value="{% if event.settings.display_net_prices %}{{ var.initial_price.net|money_numberfield:event.currency }}{% else %}{{ var.initial_price.gross|money_numberfield:event.currency }}{% endif %}"
+                                                                            >
+                                                                        </div>
+                                                                    {% elif not var.display_price.gross %}
+                                                                    {% elif event.settings.display_net_prices %}
+                                                                        {{ var.display_price.net|money:event.currency }}
+                                                                    {% else %}
+                                                                        {{ var.display_price.gross|money:event.currency }}
+                                                                    {% endif %}
+                                                                    {% if item.original_price or var.original_price %}
+                                                                        </ins>
+                                                                    {% endif %}
+                                                                    {% if item.includes_mixed_tax_rate %}
+                                                                        {% if event.settings.display_net_prices %}
+                                                                            <small>{% trans "plus taxes" %}</small>
+                                                                        {% else %}
+                                                                            <small>{% trans "incl. taxes" %}</small>
+                                                                        {% endif %}
+                                                                    {% elif var.display_price.rate and var.display_price.gross and event.settings.display_net_prices %}
+                                                                        <small>{% blocktrans trimmed with rate=var.display_price.rate|floatformat:-2 name=var.display_price.name %}
+                                                                            <strong>plus</strong> {{ rate }}% {{ name }}
+                                                                        {% endblocktrans %}</small>
+                                                                    {% elif var.display_price.rate and var.display_price.gross %}
+                                                                        <small>{% blocktrans trimmed with rate=var.display_price.rate|floatformat:-2 name=var.display_price.name %}
+                                                                            incl. {{ rate }}% {{ name }}
+                                                                        {% endblocktrans %}</small>
+                                                                    {% endif %}
+                                                                {% endif %}
+                                                            </div>
+                                                            {% if var.cached_availability.0 == 100 or var.initial %}
+                                                                <div class="col-md-2 col-xs-6 availability-box available">
+                                                                    {% if c.max_count == 1 or not c.multi_allowed %}
+                                                                        <label class="item-checkbox-label">
+                                                                            <input type="checkbox" value="1"
+                                                                                   {% if var.initial %}checked="checked"{% endif %}
+                                                                                   id="cp_{{ form.cartpos.pk }}_variation_{{ item.id }}_{{ var.id }}"
+                                                                                   name="cp_{{ form.cartpos.pk }}_variation_{{ item.id }}_{{ var.id }}"
+                                                                                   data-exclusive-prefix="cp_{{ form.cartpos.pk }}_variation_{{ item.id }}_"
+                                                                                   title="{% blocktrans with item=item.name var=var.name %}Amount of {{ item }} – {{ var }} to order{% endblocktrans %}">
+                                                                        </label>
+                                                                    {% else %}
+                                                                        <input type="number" class="form-control input-item-count" placeholder="0" min="0"
+                                                                               {% if var.initial %}value="{{ var.initial }}"{% endif %}
+                                                                               max="{{ c.max_count }}"
+                                                                               pattern="\d*"
+                                                                               id="cp_{{ form.cartpos.pk }}_variation_{{ item.id }}_{{ var.id }}"
+                                                                               name="cp_{{ form.cartpos.pk }}_variation_{{ item.id }}_{{ var.id }}">
+                                                                    {% endif %}
+                                                                </div>
+                                                            {% else %}
+                                                                {% include "pretixpresale/event/fragment_availability.html" with price=var.display_price.gross avail=var.cached_availability.0 event=event item=item var=var %}
+                                                            {% endif %}
+                                                            <div class="clearfix"></div>
+                                                        </div>
+                                                    {% endfor %}
+                                                </div>
+                                            </details>
+                                        {% else %}
+                                            <div class="row-fluid product-row simple">
+                                                <div class="col-md-8 col-xs-12">
+                                                    {% if item.picture %}
+                                                        <a href="{{ item.picture.url }}" class="productpicture"
+                                                           data-title="{{ item.name|force_escape|force_escape }}"
+                                                                {# Yes, double-escape to prevent XSS in lightbox #}
+                                                           data-lightbox="{{ item.id }}">
+                                                            <img src="{{ item.picture|thumb:'60x60^' }}"
+                                                                 alt="{{ item.name }}"/>
+                                                        </a>
+                                                    {% endif %}
+                                                    <div class="product-description {% if item.picture %}with-picture{% endif %}">
+                                                        <h4>
+                                                            <label for="cp_{{ form.cartpos.pk }}_item_{{ item.id }}">{{ item.name }}</label>
+                                                        </h4>
+                                                        {% if item.description %}
+                                                            <div class="product-description">
+                                                                {{ item.description|localize|rich_text }}
+                                                            </div>
+                                                        {% endif %}
+                                                        {% if item.do_show_quota_left %}
+                                                            {% include "pretixpresale/event/fragment_quota_left.html" with avail=item.cached_availability %}
+                                                        {% endif %}
+                                                        {% if item.min_per_order and item.min_per_order > 1 %}
+                                                            <p>
+                                                                <small>
+                                                                    {% blocktrans trimmed with num=item.min_per_order %}
+                                                                        minimum amount to order: {{ num }}
+                                                                    {% endblocktrans %}
+                                                                </small>
+                                                            </p>
+                                                        {% endif %}
+                                                    </div>
+                                                </div>
+                                                <div class="col-md-2 col-xs-6 price">
+                                                    {% if not c.price_included %}
+                                                        {% if item.original_price %}
+                                                            {% if event.settings.display_net_prices %}
+                                                                <del>{{ item.original_price.net|money:event.currency }}</del>
+                                                            {% else %}
+                                                                <del>{{ item.original_price.gross|money:event.currency }}</del>
+                                                            {% endif %}
+                                                            <ins>
+                                                        {% endif %}
+                                                        {% if item.free_price %}
+                                                            <div class="input-group input-group-price">
+                                                                <span class="input-group-addon">{{ event.currency }}</span>
+                                                                <input type="number" class="form-control input-item-price" placeholder="0"
+                                                                        min="{% if event.settings.display_net_prices %}{{ item.display_price.net|money_numberfield:event.currency }}{% else %}{{ item.display_price.gross|money_numberfield:event.currency }}{% endif %}"
+                                                                        name="cp_{{ form.cartpos.pk }}_item_{{ item.id }}_price"
+                                                                        title="{% blocktrans trimmed with item=item.name %}Modify price for {{ item }}{% endblocktrans %}"
+                                                                        value="{% if event.settings.display_net_prices %}{{ item.initial_price.net|money_numberfield:event.currency }}{% else %}{{ item.initial_price.gross|money_numberfield:event.currency }}{% endif %}"
+                                                                        step="any">
+                                                            </div>
+                                                        {% elif not item.display_price.gross %}
+                                                        {% elif event.settings.display_net_prices %}
+                                                            {{ item.display_price.net|money:event.currency }}
+                                                        {% else %}
+                                                            {{ item.display_price.gross|money:event.currency }}
+                                                        {% endif %}
+                                                        {% if item.original_price %}
+                                                            </ins>
+                                                        {% endif %}
+                                                        {% if item.includes_mixed_tax_rate %}
+                                                            {% if event.settings.display_net_prices %}
+                                                                <small>{% trans "plus taxes" %}</small>
+                                                            {% else %}
+                                                                <small>{% trans "incl. taxes" %}</small>
+                                                            {% endif %}
+                                                        {% elif item.display_price.rate and item.display_price.gross and event.settings.display_net_prices %}
+                                                            <small>{% blocktrans trimmed with rate=item.display_price.rate|floatformat:-2 name=item.display_price.name %}
+                                                                <strong>plus</strong> {{ rate }}% {{ name }}
+                                                            {% endblocktrans %}</small>
+                                                        {% elif item.display_price.rate and item.display_price.gross %}
+                                                            <small>{% blocktrans trimmed with rate=item.display_price.rate|floatformat:-2 name=item.display_price.name %}
+                                                                incl. {{ rate }}% {{ name }}
+                                                            {% endblocktrans %}</small>
+                                                        {% endif %}
+                                                    {% endif %}
+                                                </div>
+                                                {% if item.cached_availability.0 == 100 or item.initial %}
+                                                    <div class="col-md-2 col-xs-6 availability-box available">
+                                                        {% if c.max_count == 1 or not c.multi_allowed %}
+                                                            <label class="item-checkbox-label">
+                                                                <input type="checkbox" value="1"
+                                                                       {% if item.initial %}checked="checked"{% endif %}
+                                                                       name="cp_{{ form.cartpos.pk }}_item_{{ item.id }}"
+                                                                       id="cp_{{ form.cartpos.pk }}_item_{{ item.id }}">
+                                                            </label>
+                                                        {% else %}
+                                                            <input type="number" class="form-control input-item-count" placeholder="0" min="0"
+                                                                   pattern="\d*"
+                                                                   max="{{ c.max_count }}"
+                                                                   {% if item.initial %}value="{{ item.initial }}"{% endif %}
+                                                                   name="cp_{{ form.cartpos.pk }}_item_{{ item.id }}"
+                                                                   id="cp_{{ form.cartpos.pk }}_item_{{ item.id }}"
+                                                                   title="{% blocktrans with item=item.name %}Amount of {{ item }} to order{% endblocktrans %}">
+                                                        {% endif %}
+                                                    </div>
+                                                {% else %}
+                                                    {% include "pretixpresale/event/fragment_availability.html" with price=item.display_price.gross avail=item.cached_availability.0 event=event item=item var=0 %}
+                                                {% endif %}
+                                                <div class="clearfix"></div>
+                                            </div>
+                                        {% endif %}
+                                    {% endfor %}
                                 </fieldset>
                             {% empty %}
                                 <em>
diff --git a/src/pretix/presale/views/event.py b/src/pretix/presale/views/event.py
index c3fefd0ff..977c12ac9 100644
--- a/src/pretix/presale/views/event.py
+++ b/src/pretix/presale/views/event.py
@@ -58,9 +58,10 @@ def item_group_by_category(items):
     )
 
 
-def get_grouped_items(event, subevent=None, voucher=None, channel='web', require_seat=0, base_qs=None):
+def get_grouped_items(event, subevent=None, voucher=None, channel='web', require_seat=0, base_qs=None, allow_addons=False,
+                      quota_cache=None):
     base_qs = base_qs if base_qs is not None else event.items
-    items = base_qs.using(settings.DATABASE_REPLICA).filter_available(channel=channel, voucher=voucher).select_related(
+    items = base_qs.using(settings.DATABASE_REPLICA).filter_available(channel=channel, voucher=voucher, allow_addons=allow_addons).select_related(
         'category', 'tax_rule',  # for re-grouping
         'hidden_if_available',
     ).prefetch_related(
@@ -124,7 +125,7 @@ def get_grouped_items(event, subevent=None, voucher=None, channel='web', require
     else:
         items = items.filter(requires_seat=0)
     display_add_to_cart = False
-    external_quota_cache = event.cache.get('item_quota_cache')
+    external_quota_cache = quota_cache or event.cache.get('item_quota_cache')
     quota_cache = external_quota_cache or {}
 
     if subevent:
@@ -291,7 +292,7 @@ def get_grouped_items(event, subevent=None, voucher=None, channel='web', require
 
             item._remove = not bool(item.available_variations)
 
-    if not external_quota_cache and not voucher:
+    if not external_quota_cache and not voucher and not allow_addons:
         event.cache.set('item_quota_cache', quota_cache, 5)
     items = [item for item in items
              if (len(item.available_variations) > 0 or not item.has_variations) and not item._remove]
diff --git a/src/pretix/static/pretixpresale/js/ui/main.js b/src/pretix/static/pretixpresale/js/ui/main.js
index b1410c49a..42b945544 100644
--- a/src/pretix/static/pretixpresale/js/ui/main.js
+++ b/src/pretix/static/pretixpresale/js/ui/main.js
@@ -114,6 +114,15 @@ var form_handlers = function (el) {
         );
     });
 
+    el.find("input[data-exclusive-prefix]").each(function () {
+        var $others = $("input[name^=" + $(this).attr("data-exclusive-prefix") + "]:not([name=" + $(this).attr("name") + "])");
+        $(this).on('click change', function () {
+            if ($(this).prop('checked')) {
+                $others.prop('checked', false);
+            }
+        });
+    });
+
     el.find("input[name*=question], select[name*=question]").change(questions_toggle_dependent);
     questions_toggle_dependent();
 };
diff --git a/src/pretix/static/pretixpresale/scss/_checkout.scss b/src/pretix/static/pretixpresale/scss/_checkout.scss
index a139fabd1..3ceae65a4 100644
--- a/src/pretix/static/pretixpresale/scss/_checkout.scss
+++ b/src/pretix/static/pretixpresale/scss/_checkout.scss
@@ -87,3 +87,12 @@
     display: none;
   }
 }
+
+.addons {
+  fieldset {
+    margin-top: 20px;
+    &:first-child {
+      margin-top: 0;
+    }
+  }
+}
diff --git a/src/pretix/static/pretixpresale/scss/_event.scss b/src/pretix/static/pretixpresale/scss/_event.scss
index eaf1cae37..fb123c9ea 100644
--- a/src/pretix/static/pretixpresale/scss/_event.scss
+++ b/src/pretix/static/pretixpresale/scss/_event.scss
@@ -1,5 +1,11 @@
 .product-row {
     border-top: 1px solid $table-border-color;
+    .addons &:first-child {
+        border-top: 2px solid $table-border-color;
+    }
+    .addons &:last-child {
+        border-bottom: 2px solid $table-border-color;
+    }
 
     &:last-child {
     }
diff --git a/src/tests/api/test_items.py b/src/tests/api/test_items.py
index 0dccfddc4..025615c06 100644
--- a/src/tests/api/test_items.py
+++ b/src/tests/api/test_items.py
@@ -352,7 +352,8 @@ def test_item_detail_addons(token_client, organizer, event, team, item, category
         "min_count": 0,
         "max_count": 1,
         "position": 0,
-        "price_included": False
+        "multi_allowed": False,
+        "price_included": False,
     }]
     resp = token_client.get('/api/v1/organizers/{}/events/{}/items/{}/'.format(organizer.slug, event.slug,
                                                                                item.pk))
@@ -575,6 +576,7 @@ def test_item_create_with_addon(token_client, organizer, event, item, category,
                     "min_count": 0,
                     "max_count": 10,
                     "position": 0,
+                    "multi_allowed": False,
                     "price_included": True
                 }
             ]
@@ -620,6 +622,7 @@ def test_item_create_with_addon(token_client, organizer, event, item, category,
                     "min_count": 0,
                     "max_count": 10,
                     "position": 0,
+                    "multi_allowed": False,
                     "price_included": True
                 }
             ]
@@ -663,6 +666,7 @@ def test_item_create_with_addon(token_client, organizer, event, item, category,
                     "min_count": 110,
                     "max_count": 10,
                     "position": 0,
+                    "multi_allowed": False,
                     "price_included": True
                 }
             ]
@@ -706,6 +710,7 @@ def test_item_create_with_addon(token_client, organizer, event, item, category,
                     "min_count": -1,
                     "max_count": 10,
                     "position": 0,
+                    "multi_allowed": False,
                     "price_included": True
                 }
             ]
@@ -920,6 +925,7 @@ def test_item_update(token_client, organizer, event, item, category, item2, cate
                     "min_count": 0,
                     "max_count": 10,
                     "position": 0,
+                    "multi_allowed": False,
                     "price_included": True
                 }
             ]
@@ -1011,6 +1017,7 @@ def test_item_update_with_addon(token_client, organizer, event, item, category):
                     "min_count": 0,
                     "max_count": 10,
                     "position": 0,
+                    "multi_allowed": False,
                     "price_included": True
                 }
             ]
@@ -1372,6 +1379,7 @@ TEST_ADDONS_RES = {
     "min_count": 0,
     "max_count": 10,
     "position": 1,
+    "multi_allowed": False,
     "price_included": False
 }
 
@@ -1410,6 +1418,7 @@ def test_addons_create(token_client, organizer, event, item, category, category2
             "min_count": 0,
             "max_count": 10,
             "position": 1,
+            "multi_allowed": False,
             "price_included": False
         },
         format='json'
@@ -1427,6 +1436,7 @@ def test_addons_create(token_client, organizer, event, item, category, category2
             "min_count": 10,
             "max_count": 20,
             "position": 2,
+            "multi_allowed": False,
             "price_included": False
         },
         format='json'
@@ -1441,6 +1451,7 @@ def test_addons_create(token_client, organizer, event, item, category, category2
             "min_count": 10,
             "max_count": 20,
             "position": 2,
+            "multi_allowed": False,
             "price_included": False
         },
         format='json'
diff --git a/src/tests/presale/test_cart.py b/src/tests/presale/test_cart.py
index cefe75d85..10304cbe0 100644
--- a/src/tests/presale/test_cart.py
+++ b/src/tests/presale/test_cart.py
@@ -2222,6 +2222,158 @@ class CartAddonTest(CartTestMixin, TestCase):
         ])
         self.cm.commit()
 
+    @classscope(attr='orga')
+    def test_multi_allowed(self):
+        cp1 = CartPosition.objects.create(
+            expires=now() + timedelta(minutes=10), item=self.ticket, price=Decimal('23.00'),
+            event=self.event, cart_id=self.session_key
+        )
+        self.addon1.max_count = 2
+        self.addon1.multi_allowed = True
+        self.addon1.save()
+        self.cm.set_addons([
+            {
+                'addon_to': cp1.pk,
+                'item': self.workshop3.pk,
+                'variation': self.workshop3a.pk
+            },
+            {
+                'addon_to': cp1.pk,
+                'item': self.workshop3.pk,
+                'variation': self.workshop3b.pk
+            }
+        ])
+        self.cm.commit()
+        assert cp1.addons.count() == 2
+
+    @classscope(attr='orga')
+    def test_number_exceeds_max(self):
+        cp1 = CartPosition.objects.create(
+            expires=now() + timedelta(minutes=10), item=self.ticket, price=Decimal('23.00'),
+            event=self.event, cart_id=self.session_key
+        )
+        self.addon1.max_count = 2
+        self.addon1.multi_allowed = True
+        self.addon1.save()
+        with self.assertRaises(CartError):
+            self.cm.set_addons([
+                {
+                    'addon_to': cp1.pk,
+                    'item': self.workshop3.pk,
+                    'variation': self.workshop3a.pk,
+                    'count': 3,
+                },
+            ])
+            self.cm.commit()
+        assert cp1.addons.count() == 0
+
+    @classscope(attr='orga')
+    def test_number_exceeds_quota(self):
+        self.workshopquota.size = 1
+        self.workshopquota.save()
+        cp1 = CartPosition.objects.create(
+            expires=now() + timedelta(minutes=10), item=self.ticket, price=Decimal('23.00'),
+            event=self.event, cart_id=self.session_key
+        )
+        self.addon1.max_count = 2
+        self.addon1.multi_allowed = True
+        self.addon1.save()
+        with self.assertRaises(CartError):
+            self.cm.set_addons([
+                {
+                    'addon_to': cp1.pk,
+                    'item': self.workshop3.pk,
+                    'variation': self.workshop3a.pk,
+                    'count': 2,
+                },
+            ])
+            self.cm.commit()
+        assert cp1.addons.count() == 1
+
+    @classscope(attr='orga')
+    def test_free_price(self):
+        self.workshop3.free_price = True
+        self.workshop3.save()
+        cp1 = CartPosition.objects.create(
+            expires=now() + timedelta(minutes=10), item=self.ticket, price=Decimal('23.00'),
+            event=self.event, cart_id=self.session_key
+        )
+        self.addon1.max_count = 5
+        self.addon1.multi_allowed = True
+        self.addon1.save()
+
+        self.cm = CartManager(event=self.event, cart_id=self.session_key)
+        self.cm.set_addons([
+            {
+                'addon_to': cp1.pk,
+                'item': self.workshop3.pk,
+                'variation': self.workshop3a.pk,
+                'count': 3,
+                'price': '24.00'
+            },
+        ])
+        self.cm.commit()
+        assert cp1.addons.count() == 3
+        assert all(a.price == Decimal('24.00') for a in cp1.addons.all())
+
+        self.cm = CartManager(event=self.event, cart_id=self.session_key)
+        self.cm.set_addons([
+            {
+                'addon_to': cp1.pk,
+                'item': self.workshop3.pk,
+                'variation': self.workshop3a.pk,
+                'count': 3,
+                'price': '5.00'
+            },
+        ])
+        self.cm.commit()
+        assert cp1.addons.count() == 3
+        assert all(a.price == Decimal('12.00') for a in cp1.addons.all())
+
+    @classscope(attr='orga')
+    def test_change_number(self):
+        cp1 = CartPosition.objects.create(
+            expires=now() + timedelta(minutes=10), item=self.ticket, price=Decimal('23.00'),
+            event=self.event, cart_id=self.session_key
+        )
+        self.addon1.max_count = 5
+        self.addon1.multi_allowed = True
+        self.addon1.save()
+        self.cm.set_addons([
+            {
+                'addon_to': cp1.pk,
+                'item': self.workshop3.pk,
+                'variation': self.workshop3a.pk,
+                'count': 3,
+            },
+        ])
+        self.cm.commit()
+        assert cp1.addons.count() == 3
+
+        self.cm = CartManager(event=self.event, cart_id=self.session_key)
+        self.cm.set_addons([
+            {
+                'addon_to': cp1.pk,
+                'item': self.workshop3.pk,
+                'variation': self.workshop3a.pk,
+                'count': 4,
+            },
+        ])
+        self.cm.commit()
+        assert cp1.addons.count() == 4
+
+        self.cm = CartManager(event=self.event, cart_id=self.session_key)
+        self.cm.set_addons([
+            {
+                'addon_to': cp1.pk,
+                'item': self.workshop3.pk,
+                'variation': self.workshop3a.pk,
+                'count': 2,
+            },
+        ])
+        self.cm.commit()
+        assert cp1.addons.count() == 2
+
     @classscope(attr='orga')
     def test_no_duplicate_items_for_same_cp(self):
         cp1 = CartPosition.objects.create(
diff --git a/src/tests/presale/test_checkout.py b/src/tests/presale/test_checkout.py
index 104a1f899..bd3bdb472 100644
--- a/src/tests/presale/test_checkout.py
+++ b/src/tests/presale/test_checkout.py
@@ -2226,8 +2226,8 @@ class CheckoutTestCase(BaseCheckoutTestCase, TestCase):
             )
 
         response = self.client.post('/%s/%s/checkout/addons/' % (self.orga.slug, self.event.slug), {
-            '{}_{}-item_{}'.format(cp1.pk, self.workshopcat.pk, self.workshop1.pk): 'on',
-            '{}_{}-item_{}'.format(cp2.pk, self.workshopcat.pk, self.workshop2.pk): self.workshop2a.pk,
+            'cp_{}_item_{}'.format(cp1.pk, self.workshop1.pk): '1',
+            'cp_{}_variation_{}_{}'.format(cp2.pk, self.workshop2.pk, self.workshop2a.pk): '1',
         }, follow=True)
         self.assertRedirects(response, '/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
@@ -2236,6 +2236,45 @@ class CheckoutTestCase(BaseCheckoutTestCase, TestCase):
             assert cp2.addons.first().item == self.workshop2
             assert cp2.addons.first().variation == self.workshop2a
 
+    def test_set_addon_multi(self):
+        with scopes_disabled():
+            ItemAddOn.objects.create(base_item=self.ticket, addon_category=self.workshopcat, multi_allowed=True, max_count=2)
+            cp1 = CartPosition.objects.create(
+                event=self.event, cart_id=self.session_key, item=self.ticket,
+                price=23, expires=now() - timedelta(minutes=10)
+            )
+
+        response = self.client.post('/%s/%s/checkout/addons/' % (self.orga.slug, self.event.slug), {
+            'cp_{}_item_{}'.format(cp1.pk, self.workshop1.pk): '2',
+        }, follow=True)
+        self.assertRedirects(response, '/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug),
+                             target_status_code=200)
+        with scopes_disabled():
+            assert cp1.addons.count() == 2
+            assert cp1.addons.first().item == self.workshop1
+            assert cp1.addons.last().item == self.workshop1
+
+    def test_set_addon_free_price(self):
+        with scopes_disabled():
+            self.workshop1.free_price = True
+            self.workshop1.save()
+            ItemAddOn.objects.create(base_item=self.ticket, addon_category=self.workshopcat)
+            cp1 = CartPosition.objects.create(
+                event=self.event, cart_id=self.session_key, item=self.ticket,
+                price=23, expires=now() - timedelta(minutes=10)
+            )
+
+        response = self.client.post('/%s/%s/checkout/addons/' % (self.orga.slug, self.event.slug), {
+            'cp_{}_item_{}'.format(cp1.pk, self.workshop1.pk): '1',
+            'cp_{}_item_{}_price'.format(cp1.pk, self.workshop1.pk): '999,99',
+        }, follow=True)
+        self.assertRedirects(response, '/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug),
+                             target_status_code=200)
+        with scopes_disabled():
+            assert cp1.addons.count() == 1
+            assert cp1.addons.first().item == self.workshop1
+            assert cp1.addons.first().price == Decimal('999.99')
+
     def test_set_addons_required(self):
         with scopes_disabled():
             ItemAddOn.objects.create(base_item=self.ticket, addon_category=self.workshopcat, min_count=1)
@@ -2332,7 +2371,7 @@ class CheckoutTestCase(BaseCheckoutTestCase, TestCase):
         response = self.client.get('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), follow=True)
         self.assertRedirects(response, '/%s/%s/checkout/addons/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
-        assert 'Workshop 1 (+ €42.00)' in response.rendered_content
+        assert '42.00' in response.rendered_content
 
     def test_set_addons_subevent_net_prices(self):
         with scopes_disabled():
@@ -2358,8 +2397,8 @@ class CheckoutTestCase(BaseCheckoutTestCase, TestCase):
         response = self.client.get('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), follow=True)
         self.assertRedirects(response, '/%s/%s/checkout/addons/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
-        assert 'Workshop 1 (+ €35.29 plus 19.00% VAT)' in response.rendered_content
-        assert 'A (+ €10.08 plus 19.00% VAT)' in response.rendered_content
+        assert '35.29' in response.rendered_content
+        assert '10.08' in response.rendered_content
 
     def test_confirm_subevent_presale_not_yet(self):
         with scopes_disabled():