Where can I sell my iPhone 5c with Virgin carrier?

Trying to switch to t-moble for iPhone 6 plus

I just sold a regular 5 16 gig to gamestop for $185. They give you cash. IF it's off contract you might get more. Also, check Gazelle. I had a 5s 64 gig, and my wife wanted it, so the phone I sold was hers.

And the 6 is great. I got that one.