So let’s say you have to determine the value of a firearm you want to purchase. If it is a new gun, that is pretty simple. Go to at least five websites and check the price. One of those sites should be Bud’s Gun Shop since they tend to have a low price. Now add in any FFL fees and shipping and you should have a pretty good idea of what would be a good deal on the gun. I know when I went looking for a Bersa it turned out I had to purchase out-of-state in order to find the model I wanted. When I purchased a Ruger SR9C it turned out to be less to buy in-state and pay the tax then to purchase online and pay FFL fees and shipping. It can also be worthwhile to look at GunBroker to see what is being charged there, but keep in mind the prices on new firearms tend to be high on GB when you add in shipping and FFL fees.
On a used firearm it is not so quick and easy. First you have to decide the condition from photos or descriptions and then work to price. I find the best place to start is GunBroker knowing the price will be slightly inflated on most items. I also check the Gun Auction website, but their search is not as user-friendly. Often a simple google search for the firearm can yield results which can prove beneficial. Keep in mind a brand new in-the-box (BNIB) older firearm will bring a much higher price than one which has holster wear and does not come with a box. I got a used S&W on GunBroker and paid almost exactly what it was worth when you include shipping and FFL fees. So if I decided to sell it tomorrow I would at least be even. At times you may run into a rare firearm which is commanding a price more than what it should. Since the Colt Python is no longer produced the prices are sky-high and will not fall back to realistic levels. There are published guides with firearm prices in them and if you are purchasing more than a few per year it would be worth the money to purchase a guide. There are also some online guides and Firearms Price Guide is an excellent free reference.