It's worth whatever you want to pay for it and as much as the seller needs for it.
If they need to get rid, then you'll get a bargain. There's plenty out there. Go look at a few, make an offer, give 'em your number, then leave it with them.
Go in at 4500........what's the worst can happen?? OK he can punch ya
but at least they know whare you're coming from.