Thrifting refers to the act of shopping at second-hand stores or shops, often run by charitable organisations such as Goodwill, Oxfam, etc., or independent stores, usually with the intent of finding clothing or furniture etc., at a lower price.
Clarification: Thrift stores are not consignment stores. Thrift stores operate on a model in which items are donated for reselling. Consignment stores operate on a model in which businesses or individuals buy secondhand items to be resold for a profit.