M.K.
There are two that I know of. One is called Kid to Kid. It is on Route 1 in Drexel Hill. You don't get a ton of $$ for your stuff though. He gives you a certain percentage up front.
The other one is a consignment shop in Narberth. It is called Twice as Nice. It is right on Main St. next to The Greeks bar. She gives you 60% of what it sells for I think.