First - the games you're trading in have to have at least .01 value on this page :Or they won't take them at all. They use the same trade in vendor (CEXchange) as walmart so their database is the same.A little caveat for those attempting this - stores are wildly misinformed or in junior detective mode about this promo.Some stores will say it's limit one/two/five/ten/no limit.Some stores will say it has to be used on a game purchase and any amount you don't spend is forfeited.Some stores will say the above but pre-orders are also allowed.Other stores that are following the actual rules of the promo will say you can put it on a gift card, game, promo, or any other item they sell.Some stores have rejected returns for store credit after buying a game because "it's special credit that must be used on a game".All stores will take a very very long time and most stores will require the games be complete and may just reject them anyways if they feel like they're saving the company from financial ruin.My wife was nice enough to take a handful of my old 360/ps3 titles for me earlier this week and they wouldn't put it on a gift card or allow use of MS Store credit or XBL subscription, said it had to be a game and any amount not spent would be forfeited.I guess i just have a bad impression of Microsoft Store because the local one has been a pain in the ass every time I went. They made me wait 20 minutes to do a return because "the guy who does them is on lunch". They also laughed when I said I would buy a xbox one when it wasn't packaged with kinect saying it was a vital part of the system and it would never happen. Just like the worst kind of "oh, you're not buying the most expensive thing and all the useless accessories with it? who cares" kind of salespeople.