I remember a specific term being used, but I don't remember exactly what it was. The word (or maybe phrase) was describing the act of buying something to wear to a party or event that the person returned when they were done with it.
It's called wardrobing
Wardrobing is a form of return fraud where an item is purchased, used, and then returned it to the store for a refund.1 It is most often done with expensive clothing - hence the name - but the practice is also common with tools, electronics, and even computers.
It's discussed in this Quora thread