BOGO – “Buy One Get One” type of discount.
Look at the examples:
- 1+1 Product (Buy 1 product and get the second one for free)
- Buy any product with certain attribute and get a certain gift
- Buy 2 products from category and choose your gift from another category
- Buy 2 certain products and be sure to choose a gift
Draw your attention to the drop-down’s value “Require to choose from product/categories”. Despite of “Allow to choose from products/categories”, user can’t place order without gift.