Cashback vs Direct Merchant Promotions: Which Saves More?

Cashback is paid to the shopper from the retailer's affiliate marketing budget after a qualifying purchase. A direct merchant promotion (a sale, a sign-up code, a member discount) lowers the price at checkout from the retailer's own margin. The two are funded from different parts of the retailer's budget, so they can usually stack: the merchant promotion lowers the price, and cashback is earned on the lower price. The combined saving is almost always larger than either alone.