retail stores, PowerUp members can get a 50% extra credit
towards a purchase when they trade-in a select used game
. (Not a member? It's free to join.) That's tied with our March mention (which was available for all shoppers and valid for any used game) as the largest trade-in credit we've seen from GameStop, which carries used Xbox 360, Nintendo Wii, and PlayStation 3 games, among others. This deal is not good on cash trades and is subject to manager's approval. Deal ends October 14.