Traded in my xbox copy of Timesplitters: Future Perfect at GameCrazy the other day and got $17.60 in store credit for it (as an MVP member). I used the trade in value to get Dark Cloud 2 (priced at $17.99). Almost an even swap.
Currently TS:FP is only selling for about $13-15 on ebay.
Nice to hear somebody actually got a good deal from a turn in. I tried to trade in a few games that were in flawless shape and they wanted to give me $1.00. One of the games were Mickey Mouse magical mirror. (which I bought a few days prior and the game sucked horribly!) They said they had a whole bunch in stock and nobody seemed to want them.