Upselling

A sales strategy where the seller will provide opportunities to purchase related products or services, often for the sole purpose of making a larger sale. A popular example of upselling happens when a fast-food customer orders a hamburger, and they are asked by their cashier “Do you want fries with that?”, in an attempt to get them to purchase more food. Other examples of products that are upsold are warranties on electronics purchases, and the purchase of a carwash after you purchased gas at the gas station. (Source: BusinessDictionary)