# Discount bundles
> For the complete documentation index, see [llms.txt](https://docs.talon.one/llms.txt).
Let's create a [promotion rule](/docs/product/rules/overview.md#promotion-rules) that awards customers with a $50 pro-rata discount per bundle of one bike and two helmets found in their sessions.
## Create the promotion
### Cart item filters
Let's start by creating the [cart item filters](/docs/product/rules/cart-item-filters/overview.md).
We need them to identify helmets and bikes. Then we'll create a bundle based on these items.
We've already used cart item filters to check the category of cart items in the
[Different discounts for different categories tutorial](/docs/product/tutorials/sample-campaigns/discount-categories.md).
To create the cart item filter:
1. In the [Rule Builder](/docs/product/rules/overview.md) of the [campaign](/docs/product/campaigns/overview.md),
click **Cart Item Filters**.
1. Click **Add Filter**.
1. Click **Add Filter Step** and select **Filter items by conditions**.
1. Set the filter to **is equal to** `Road Bikes`.
1. In **Save As**, type `RoadBikes` and click **Save Filter**.
This cart item filter returns a **list of cart items**.
Repeat the same steps to create a filter to find items in the `Helmets` category and count them.
### Create the bundle definition
To bundle the items, let's create a [bundle definition](/docs/product/rules/create-and-manage-bundles.md):
1. Click **Bundle Definitions** > **Add Bundle Definition**.
1. In **Name**, type `1RoadBike2Helmets`.
1. In **List of cart items**, select **RoadBikes** and choose **1** item.
1. Click **Add list**.
1. In **List of cart items**, select **Helmets** and choose **2** item.
We have a bundle definition composed of one item from our `RoadBikes` cart item filter,
and two items from the `Helmets` cart item filter. The bundle definition will create as
many bundles as possible from the current state of the cart.
We know how many bundles are created thanks to the attribute.
This attribute is created automatically with the bundle definition.
### Rule
Let's create the rule to trigger the discount:
- Condition: **Check attribute value** and compose the following
expression: `is greater than or equal to 1`
This check that our bundle definition managed to create a least one bundle.
- Effect: **Discount bundles pro rata** and select:
- **Bundle definition**: `1RoadBike2Helmets`
- **Discount Name**: `$50 off a bundle of items`
- **Discount value for each bundle**: `50`
## Run the campaign
To run the campaign, we send a suitable session to the Integration API's [Update customer session][cs] endpoint.
The session contains two helmets and one road bike, which is the bundle definition.
```json title="Sending a session update" {12,22,32} showLineNumbers
CURL -X PUT https://mycompany.europe-west1.talon.one/v2/customer_sessions/my_session_id -d
'{
"customerSession": {
"profileId": "{{integrationId}}",
"state": "closed",
"cartItems": [
{
"name": "ProductC",
"sku": "sku-00004",
"quantity": 2,
"price": 200,
"Category": "Road Bikes",
"weight": 0,
"position": 0,
"attributes": {}
},
{
"name": "ProductD",
"sku": "sku-00005",
"quantity": 1,
"price": 49.99,
"Category": "Helmets",
"weight": 0,
"position": 0,
"attributes": {}
},
{
"name": "ProductE",
"sku": "sku-00006",
"quantity": 1,
"price": 39.99,
"Category": "Helmets",
"weight": 0,
"position": 0,
"attributes": {}
}
],
"couponCodes": [
""
],
"referralCode": "",
"attributes": {},
"additionalCosts": {}
},
"responseContent": []
}'
```
We receive this response, which shows the `setDiscountPerItem` effect for _each item_.
As we saw in the [Different discounts for different categories tutorial](/docs/product/tutorials/sample-campaigns/discount-categories.md),
the `position` property represents which item is impacted by the effect based
on the item's position in the `cartItems` array sent in the update request.
```json title="Response" {15,16,33,34,51,52} showLineNumbers
{
"createdCoupons": [],
"createdReferrals": [],
"effects": [
{
"campaignId": 9986,
"rulesetId": 41128,
"ruleIndex": 0,
"ruleName": "$50 on Bundle: 1 Road Bike & 2 Helmets",
"effectType": "setDiscountPerItem",
"evaluationGroupID": 38,
"evaluationGroupMode": "stackable",
"props": {
"name": "$50 off a bundle of items#0",
"value": 34.49,
"position": 0,
"subPosition": 0,
"totalDiscount": 50,
"bundleIndex": 0,
"bundleName": "1bike2helmets"
}
},
{
"campaignId": 9986,
"rulesetId": 41128,
"ruleIndex": 0,
"ruleName": "$50 on Bundle: 1 Road Bike & 2 Helmets",
"effectType": "setDiscountPerItem",
"evaluationGroupID": 38,
"evaluationGroupMode": "stackable",
"props": {
"name": "$50 off a bundle of items#1",
"value": 8.62,
"position": 1,
"subPosition": 0,
"totalDiscount": 50,
"bundleIndex": 0,
"bundleName": "1bike2helmets"
}
},
{
"campaignId": 9986,
"rulesetId": 41128,
"ruleIndex": 0,
"ruleName": "$50 on Bundle: 1 Road Bike & 2 Helmets",
"effectType": "setDiscountPerItem",
"evaluationGroupID": 38,
"evaluationGroupMode": "stackable",
"props": {
"name": "$50 off a bundle of items#2",
"value": 6.89,
"position": 2,
"subPosition": 0,
"totalDiscount": 50,
"bundleIndex": 0,
"bundleName": "1bike2helmets"
}
}
]
}
```
:::tip Key Takeaways
- You can bundle items with a cart item filter or use the [bundle feature](/docs/product/rules/create-and-manage-bundles.md).
:::
## Related pages
- [Use conditions](/docs/product/rules/conditions/overview.md) and [effects](/docs/product/rules/effects/overview.md)
- [Create and manage item bundles](/docs/product/rules/create-and-manage-bundles.md)
- [Cart item filters](/docs/product/rules/cart-item-filters/overview.md)
- [Application cart item filters](/docs/product/applications/manage-application-cart-item-filters.md)
- [setDiscountPerItem effect](/docs/dev/integration-api/api-effects.md#setdiscountperitem)
[cs]: /integration-api#tag/Customer-sessions/operation/updateCustomerSessionV2