You just realizing this now? I stopped trading in games years ago,.

Sell on Ebay. I can't stress that enough

Trading in killzone?
You must be insane!

I always trade staff in gamestop, but only when they have the 50% and I'm a pro member so that's 60%,new games you have 30 days and you get 30 dollars on credit, and this cases games like shadow fall sell it in ebay , problem is you have to pay 10% to ebay , games like xenoblade chronicles you can sell it for 70 dollar in ebay.

That's why I sell games on craigslist

I would not support GameStop because of their unacceptable business practices!!!

Most Nintendo gamers collect their games hence why second hand market prices are higher then normal, at least here anyway.

Go to like and EB and you can see 100s of PS3 games used. Go to DS section and al you see used is mainly shovelware.

They are not absurd your selling it to a company that's selling it to the consumer. They generate most of their profit through used game sells, gamestop isn't buying the game to play it for themselves they want to make a 10-15 dollar profit.
If you sold your game directly to a consumer rather then a middle man you would see the price of your copy rise 5-15 dollars.

That's why I quit trading in games. I traded in 4 PS2 games a while ago (before the Wii/360/PS3 came out) and I got a whopping $11 total.