iPhone 5C Pricing

[Delorean2006]

My Girlfriend wants to get rid of her iPhone 5C for a 5S, she doesn't care that theres a new iPhone coming out in roughly september, but she wants a 5S...in gold of course, so how much could I sell her 5C for, its a green 32gb for sprint with some minor scratches on it and how could i avoid her phone from getting a bad ESN on it so if i sell it, the next person can actually use it

 

[Cubytus]

Just bought, already on sale? What's wrong with that phone? Of course I'd like to buy an unlocked 5C given the chance.