Gamestop offering trade-in deals through March 14

Trading in used video games at Gamestop is usually a good way to get ripped off -- but between now and March 14, you'll get a better deal.

Calling it "the biggest trade event ever," the retailer is offering 50% bonus credit for any and all game trade-ins. As Joystiq discovered, adding the bonus puts recent popular titles like Call of Duty: Modern Warfare 2, New Super Mario Bros. Wii, Dante's Inferno, and BioShock 2 at around the $35 mark.
That's not bad, as Gamestop prices go -- but January smash Mass Effect 2 will net you a decidedly healthy $52, only a few bucks less than the new price of the game. Older, less popular games will still earn you a pennies, but forget about trading in those outdated sports games. 50% of nothing is still nothing.