A guy from IGN posted this, and I think it's frickin' clever:

How to scam the gameing stores
dont trade 2 games when you only need to trade 1 in...heres how you do it.

step 1. say you want to take gta:vc back. go t bestbuy, walmart, any store that sells games. and say it is scratched can i get a new one. they should say yes. you go get it and take it with you. if they take the plastic off your still good unles they break the seal. if they do just go to a dif store and try again.

step 2. take the "new unopened" game to a dif store. and say you got it as a gift, but already have the game. they will see the seal and take it back, and they will give you store credit and you walk back to get the new game you want.

step 3. go home and play it all day long.

-Johnny_KNoxville04

Pretty clever, if you ask me.

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Alias: and that's the story of my yeast infection