IPhone resell price/used 8 GB factory reset prices?

I recently got my phone upgraded to the iPhone 6 for free and now my old 8 GB iPhone 4s is just useless, if I did sell it how much would this go for?
Has wall adapter for charger, charger cord and earbuds, no damages, scratches or cracks.

I would not pay more than $50 for it. As you say, it's pretty useless at only 8GB of memory, less once you take away what the OS and installed apps use. Add to the fact that Apple is no longer updating the OS (soon), but then why even bother with less than 32 GB?