Best place to trade in 64GB iPhone 4S (Sprint)?

[BNoyes]

I needed an upgrade so I just bought a new iphone from the Best Buy sale and was wondering what to do with my old iPhone 4S. I know it's not worth much, but any auggestions on where to get the most out of it?

 

[ArugulaZ]

Here, or Ebay. I think Ebay's offering a deal where they throw in an extra hundred dollars if you sell your phone on their site.