Game Stop: Buy One Pre-Owned Game, Get One FREE! May 20, 2010 This post may contain a link to an affiliate. See my disclosure policy for more information. See that ad? It’s wrong! They are supposed to be doing a buy two get one FREE sale, but the coupon code is buy one pre-owned game and get one FREE! Just use coupon code BUYTWO at checkout. Thanks, SwagGrabber!