D80 second hand price?

I'd pay my FRIEND the going rate for a used camera...  Key words are USED vs FACTORY REFURBISHED.

There are several camera companies around that send used cameras to Nikon to be refurbished and they have a store you can go to, or send your camera to in the event something is wrong.  Usually REFURBISHED cameras will have a warranty of 6 months or so, and buying "REFURBISHED" instead of simply "USED" means that any mysterious issues will likely have been resolved with the camera before you've put your hands on it...Also... FACTORY REFURBISHED means that it was done by Nikon.  Ask before you buy.  You'll pay a bit more for Refurbished but it's worth it.  I buy quite a lot of things this way...