How much could I sell a chipped but working iPhone 4 for really?

I don't want to sell to a business because I probably wouldn't get a good price at all. It's a white, iPhone 4 8GB. Works perfectly fine no cracked screen it just has a lot of nicks and chips on the side, which are easily hidden with a phone case. Other then that it's a good phone, not unlocked but with AT&T. What could I realistically ask for for this phone? I tried eBay but most phones listed are broken for parts or cracked screen, mine isn't that bad.

If you unlock it (a phone call to AT&T and they will unlock it for free) I will give you $100 for it.
You can contact me at aalez@msn.com
Also there's a great website that buys old and broken electronics. And they offer best prices on the market.
Check it out - http://sellbrokenelectronics.wordpress.com