This article requires the Freebies addon from the Neto addon store.
You can automatically add a free product to the customer’s shopping cart when they select a product. This can be done two ways:
To add free products to a product from the Neto dashboard, navigate to Products > View Products
Edit the product you wish to make changes to.
Scroll down to the Freebies section.
Select the product from the list. You can add more than one product.
Save changes. When the product is added to the shopping cart, the customer can choose which of the free products they want to add to their order.