How much money does gamestop give you if you sell a wii?

I tried selling my used Wii that has nothing broken and everything was working properly. They said that they would offer me $15.00 U.S. dollars for it. If my calculations are correct, that is about 2% of the original price when it was first sold. The man at the front desk told my that I should just keep it, and i think you should too.