How much should a used D300 sell for?

Not a D300s, but a plain D300. Comes with a Nikkor 18-70mm F3.5-4.5G lens.

Depends on how old it is.a camera 3 yrs old will sell at around 600-700$ depending on how much you can squeeze out… The lens shud sell at around 200$ .

Basically it will sell for whatever someone is willing to pay for it.

$500

Ebay will give you a good indication of fair market value.