Can I trade in a game at gamestop if I got it for free?

Well I had a coupon for a buy 2 used get one free used game and i gOt borderlands, ninja gaide sigma, and dante's inferno. They were 19.99, 12.99, and 17.99 respectively so I ended up getting ninja gaiden for free. I do not like borderlands or ninja gaiden and Im wondering If I can trade these two in for another two games for an equal price even though one was free.