Buy One Get One (or BOGO for short) is one of the best offers you can use to clear out and move inventory and generate more cash. People have to buy more to get the offer, so you get more money. The customer will get for free the cheapest product of the products that he added to the cart. Then on the cart page, the discount is visible in the item subtotal. Reward the customer with a free product when he purchases other products and allow him to choose the gift.