try-buy

The act of going into a store or shop, not to actually by anything, but just take advantage of the free samples.

Examples:

Going into Costco just to eat the free stuff
Going into an expensive store just to spray the tester bottle of perfume on yourself

Girl 1: Wow, that perfume smells really fancy and costly!
Girl 2: lol she just try-buyed it from Victoria's Secret, ain't nothing special