How to set up the promo 'Buy one product, get another one'?
First of all, it's worth to note that BOGO promo ("Buy one, get one") works a bit differently than similar promotions with other product quantity.
If you don't know how to configure the promo 'Buy one product, get another one' in Special Promotions extension, please, check the steps below.
Actions: Set up 'Percent of product Pprice discount' for a single SKU as shown in the example:
The trick here is that we give 50% discount for a pair of products with the same price, so effectively we give one of the products for free.