We've got a couple of used copies at the Gamecrazy I work at for $14.99
Sadly, the game didn't sell too well, and the customers I did recommend it to didn't really appreciate it and traded it back in.
It's a good game if you're a big fan of the previous titles in the series like I am though.
I work for GC and I can vouch for the trade prices changing based on stock levels. I haven't figured out the specifics yet though.
I know some(usually newer) games have a fixed trade price, and some are subject to quantity on hand. Usually we have to have 5 or more in stock for it to affect...