Question

What is term for convincing a customer to buy a larger quantity of an item or a more expensive item?

Answer 1

Up selling, pretty much to increase profits made by the store by tricking the customer into buying more expensive products.

Answer 2

Upselling. As the dictionary states, "Upselling is a sales technique where a seller induces the customer to purchase more expensive items, upgrades or other add-ons in an attempt to make a more profitable sale."