Selecting a gift item in the cart will throw a generic exception if it has no price, especially if the store uses an external tax service. The customer can't go ahead selecting it.

Since the price is a requirement, the expected behavior is that the item/gift shouldn't be offered.

• to register a new item or to update it to be without price
• to create a gift promotion offering this item
• to create a cart where the item will be offered
• try to select the gift; an error will be presented

To register a price, which is a requirement for every item that will be active and sold, even as a gift.