Blue Book is a great reference for Valuation. The problem is, demand dictates the value. Buying from an Auction, a poorly graded pistol, valued @ $ 100 can fetch as high as demand dictates as long as there are buyers interested. For collectors desperate for particular firearms, sometimes, bids goes outrageously out of control. For other buyers like most of us, condition matters. If you feel like buying a reasonably prices used firearm, go for it. The bottom line is, do your research first. Set your pricing limits. Visually check the firearm, fire it if the seller agrees and buy it if you are satisfied. Remember, no amount of money can satisfy your desire for a specific firearm if you do not own one. I have a friend who got a Browning Challenger from an auction few months back. Bids opened @ $ 250. His limit was $ 600 and eventually paid a little over $ 500. It was in better than expected condition. As posted above, be aware of parts including magazine. These are a little expensive and very hard to find should you require one.