Wal-mart is the best about not having a receipt. However, being right after Christmas, you might have to stand in line at Customer Service for a really long time. Target also will do a no-receipt return using your driver's license. You get a $70 max per calendar year, but a DS game is less than that so you should have no problem. Plus, Target's games are usually more expensive, so your store credit will be slightly higher than Wal-Mart's.