The online community of knife collectors, A Knife Family Forged in Steel
My experience recently, hard to find mint/near mint knives.....The majority of knives I picked up to look at where clean to handle on the outside, but the blades where filty...no attempts to clean the knife up was shocking to see.
Of course, a knife is only worth what someone will pay for it. The economy has a lot to do with it. If I see a knife I like, one that I want and collect, I'll pay for it - though I cringe towards $100. I enjoy many that I paid only 10-40 $ for. One of my favorite I paid $11 shipped.
For me though, I don't buy to re-sell, I buy to keep and enjoy and know that I will pass them down to Grandkids, give them something that Grandpa really liked.