(Use Case) Require Purchase Together with Another Product

This is a configuration example for restricting eligible items so they cannot be purchased on their own and must be bought together with other products.

Use case

Use this when you want to prevent standalone purchases and require customers to always buy the product as part of a set with other items.

Result

The following behavior applies based on the cart contents:

Eligible items only → Not allowed
Eligible items + other products (non-eligible) → Allowed

Configuration example

Field	Value
① Title	Enter any title
② Limit details > Bundle limit level	Complementary
③ Eligible items	Set the products you want to restrict
⑤ Product message	Enter any message
⑥ Alert message > Display timing	Fixed to Checkout only (cannot be changed)
⑥ Alert message > Message	Enter any message

When Complementary is selected, the alert message Display timing is automatically fixed to Checkout only. Displaying an error on the cart page is not supported.

Configuration tips

Setting Bundle limit level to Complementary prevents customers from placing an order when only eligible items are in the cart.
As long as at least one non-eligible item is in the cart alongside the eligible items, the purchase is allowed.
The alert message is displayed on the checkout page only. Displaying an error on the cart page is not supported.
If there are specific products you do not want treated as non-eligible items, add them to ④ Excluded items.