up-sell

Up-sell is a marketing term for the practice of suggesting higher priced products or services to a customer who is considering a purchase. An up-sell offer is typically for a better version of the same product or service you are considering, such as a gym membership with more privileges, or a faster computer. The most ubiquitous example of up-sell is likely the oft-spoken (if ungrammatical) fast food phrase: "Would you like to biggie-size that?"

A related practice, cross-sell, involves suggesting additional items to a customer making a purchase.