Need a little help here

Ok, so here is the deal. I have had my iPhone and AT&T service for about 9 months, and its ok, certainly could be better. I have the iPhone 3G 8GB. In my area, which is St.Louis my signal randomly goes from 3G to Edge, back to 3G in a minute or 2, then back to Edge, all while standing in the same area. Normally I have 3G coverage everywhere I go, but not recently. I called AT&T and asked them if there were any outages in my area. Negative. That and the frequent and ever so popular "call failed".

And after several months of owning the iPhone, Its not really all what it's cracked up to be, IMO that is. I don't need the iPod feature, as I have one, and the apps I can honestly do without. I originally came from a BlackBerry, and I think I want to go back. I have messed around with the Storm 2, and I like it, a lot!

Now here is where I need help at. I called Verizon and they told me I have to have a deposit of $400 to sign up, and the cost of the phone $179. I want to sell my iPhone and get as much as I possibly can out of it, so there is not that much coming out of my pocket. My iPhone is in MINT condition, not a scratch on it, anywhere, I had it put in an INCASE protective case the day I got it, and also put InvisibleShield screen protector on it as well. The phone is jailbroken and unlocked on the latest firmware (3.1.2) I have the original box, manual, cloth, earbuds, usb charger, etc. What do you guys think I could sell it for. Thanks in advance.