How much do I sell my ole iPhone 4?

I have an iPhone 4 with car and home charger, a hard case (similar to a otterbox), and 2 other cheap rubber cases. And abt 20-30 apps. If I can leave them on the phone. But the phone won't be able to activate so it can only get online on Wi-Fi. And it can't ever be able to be activated. This is because we no longer have phones because we owe $700 to Verizon and they told us that if we sell the phone it can only get on Wi-Fi. So that's all the phones for. So you can download games, get on Wi-Fi, and play apps that don't require Internet. So how much is it worth for it? Saving to get an iPad or iphone5.

I say for 150 because if it only works with Wi-Fi then it's not worth it because you could go to the store and get a new iphone 4 for 50$

If you can't use it as a phone obviously the price goes down dramatically. You may want to see what apple will give you for it by recycling it on their site, they will give you store credit for it. See: http://www.justtext.com/messageboards/20120819083613.html