Original model, 8GB.
$175 (enough to pay my termination fee). Work is making me get a crackberry, and I refuse to be that guy carrying 2 cell phones.
The good news, since it is the original model, it can be unlocked and taken to whichever carrier you have. A few simple steps and a swap out of the sim card with the one for your carrier and away you go.
Here is the link for how to unlock it:
http://www.pcworld.com/article/137223/how_to_unlock_an_iphone.html
I would, but would hate to do it wrong and screw myself.
Most go for over $200 on e-bay, but I don't do e-bay, so this is my best shot.