If you're looking to unload them in bulk, talk to Mike at Bounty Hunter Toys. He usually only trades with store credit, but depending on what you're selling, he may pay cash outright. He isn't looking to screw you either, and should offer decent prices.
http://bountyhuntertoys.com/store/in...dex&cPath=1_72
Big B Comics also pays cash for action figures, but they are known to be VERY stingy with what they pay you for something. They will then take what you sold them and sell it in their store for a much higher price.
