Actually Gamestop.com used prices are lower than stores so corporate can boost online sales. Most newer games are only 50 while in-store they are 55. Don't know if it's for every game, but for a lot yes.
Check the website and search. I do it all the time. By the way, Bayonetta is on sale right now for both consoles. It's from the Gameday Sales. I don't know when it's over so go and check it out as fast as you can.
I'm as cheap as the next guy but I refuse to pay $55 for a used game. I'd rather buy it for the pc from steam or d2d. If it must be for console I'd check out EA online they usually have some decent deals with coupon codes or check out gamefly they also sell used games for decent prices or try Amazon or Ebay.