If you're one of the millions that returned a gift this holiday season, it most likely ends up in a warehouse for Secondipity.com. Once an electronic item has been opened, the big retailers can't put it back on the shelf. So, they sell the items to Secondipity. And Because the company is a clearing house, they can sell at discounts up to 80%.
But if you are looking to unload some of the unused items in your house, there are several websites that can put cash in your pocket. Threadup.com will give you money for gently used clothing. They'll send the bag, all you have to do is load it up.