Hey, I don't know if I'm going to be helpful, but I'll give it a shot.
The obvious place to check would be eBay, and after searching completed listings for new copies, they go in the mid to high $30's or lower if you're lucky. Taking a used copy, which I don't particularly like, would shave off some green.
Who, knows, though, if it's not worth your time to sit on an auction, then that price is decent, though I know people'll be able to find some magic deal. Anyway, I'm going to try and get that game when the price lowers, and hope that other people are still playing. Anyway, good luck.