Like I said, I got $675. Honestly I don't think the blue book for a used one is above say $750, and that would be what the store would sell it for. One option would be hop over to the HKpro forums, make an account, and post it in their sale subforum. Probably would get some takers.
Know the status of your weapon
Keep your muzzle oriented so that no one will be hurt if the firearm discharges
Keep your finger off the trigger until you have an adequate sight picture
Maintain situational awareness