Around $600 IMO.
Paying 600.00 for a nice used un-boxed K22 is not sky high in any form of the imagination. Just as paying 1000-1200 for a genuine NIB 17-3 depending on its options is what to realistically to expect. Better yet, go to Tulsa and walk for three days and see if you even see a NIB 17-3 at any price. You will see plenty of beaters for 800-900 or at least that's what I saw. When someone ask for an honest value, I try to give it to them. Its not in a gun dealers best interest to inflate prices, for every gun a gun dealer sells remember he has to buy that gun somewhere. Seems very logical to me. Buyers and Sellers read these value threads just the same.
John Fugate
Top 100 Gunbroker Seller Fugate Firearms