This is one of the weekly deals in-store/online, but it's an unadvertised one. It's valid until at least close of business next Tuesday.
http://www.gamestop.com/xbox-360/games/final-fantasy-xiii-2/90110
http://www.gamestop.com/ps3/games/final-fantasy-xiii-2/90109
http://www.gamestop.com/xbox-360/games/final-fantasy-xiii-2/90110
http://www.gamestop.com/ps3/games/final-fantasy-xiii-2/90109