One other thing on Amazon trade ins...
The prices fluctuate like crazy, so if it appears artificially low, wait a week. A couple examples.
I preordered Halo Launch. I used a prior $20 credit from another game purchase, so it was $40 delivered on launch (hehe) day.
I didn't like it, so I checked the trade in value. Because they were having sales, it was down to a $30 trade in value a week after release. I held on another week after all the specials, etc ran their course, and the trade in went back up to 38.75. I basically paid $1.75 to play the game...all shipping was free, including trade in.
I looked to trade in BFBC2. One week it was $11. The next week, $19.
I sound like an Amazon salesman.