How to limit an upsell discount to just 1 item with Script Editor

Overview

Offering exclusive discounts on upsell products can effectively encourage additional purchases. However, to prevent customers from applying the discount to multiple quantities of the same item, you can implement a Shopify Script that restricts the discount to only one unit per upsell product.

If you want to create a strong incentive to have a customer buy another item, you can offer a nice discount on an upsell product.

If you're offering this as an exclusive discount, you might want to limit the quantity of items that can be bought at the discounted price to 1.

Step-by-Step Guide

Log in to Shopify Admin
Access your Shopify Admin panel using your credentials.

Install and Open the Script Editor App
If not already installed, download the Script Editor app from the Shopify App Store.
Open the Script Editor from your list of installed apps.

Create a New Script
Click on Create Script.
Choose the Line Item script type.

Insert the Discount Limitation Script
Copy and paste the following script into the editor:

Input.cart.line_items.each do |line_item|
	if line_item.properties.has_key?("__upsell_id")
		if line_item.quantity > 1
			discounted_items = line_item.split(take: 1)
			Input.cart.line_items << discounted_items
		else
			line_item.change_line_price(line_item.line_price * 0.90, message: "Upsell Discount")
		end
	end
end
Output.cart = Input.cart

In this example, the discount is 10% and limited to just 1 item (see Step 5 for customizing this). Below is the explanation of the code.

Condition Check:
The script checks if the line item has the __upsell_id property, indicating it's an upsell product.
Quantity Handling:
If the quantity is greater than one, the script splits the line item, isolating one unit to apply the discount.
If the quantity is one, the script directly applies the discount.

Customize the Script
Discount Rate: Adjust 0.90 to change it from a 10% rate to reflect your desired discount. For example, use 0.80 for a 20% discount.
Discount Message: Change "Upsell Discount" to a message that aligns with your branding, such as "Exclusive Offer" or "Special Deal".

Save and Publish the Script
Click Save to apply the script.

Key Considerations
Testing: Always perform thorough testing to confirm that the discount applies exclusively to one unit of the upsell product, even if multiple quantities are added to the cart.
Script Management: If you have multiple scripts, ensure they do not conflict with each other.

Related Articles
Intro to Discounts
How Do I Apply a Discount to a Checkout Upsell Using Script Editor?

Updated on: 14/02/2025