I'm trading in GTA4, Black Ops, Reflex, COD:WAW, BF:Bad Company and NBA2k11. My total came out to $75.60 (with the promotion). More than enough to get Skyrim.
It's a pretty rough economy just trying to help people who are kinda tight on money like me.
Source: http://www.bestbuytradein.com/bb/QuoteCalculatorVideoGames.cfm# (Click on "show promotions available in stores only" in top right corner).