Thank you all for your replies, i have a collection of some early Nikon Cameras including some early F and one chrome F with red dot so i am interested on this one because it is black with plain prism and i think its value can go higher in few years, i dont afraid of buying from a new seller cause there is return policy and eBay money back guarantee, as long as i know new sellers can receive the money only one week after we received the item.The problem is not that, the problem is that i can not find an estimation for the value of this camera cause there is no other one like this on eBay.
well, obviously, if you pay $3,000 for this one, then the value of a black paint red-dot Nikon F with prism, with some signs of usage, is $3,000 and future catalogs will show that.
Sadly, that doesn't mean you will ever be able to sell it for that much. To do so you will need to find some other guy on the planet who thinks it is worth $3,000-plus.
If every other person on the planet thinks it's only worth $1,000, then you either hold onto it, with the receipt for what you paid, or you don't. That's how it work. Folks in the bitcoin market are leaning this same thing.
If I were you I'd look outside ebay and see if there is record of previous sales, by auction companies or anywhere else. If nobody else but you is bidding on this one, that's a hint.