I bought one of the "police" trade ins from my local shop and have loved it. Paid about $230-250 for it(cant' recall) , looked pretty much brand new .40S&W and only came with the magazine that was in it. Mine was a Brinks Security pistol and has the Brinks logo etched into the slide. I bought it so I could "play" with it and learn more about striker fired pistols. Over the past year, I've managed to acquire a 9mm conversion barrel and a .357 Sig barrel to go with it. I bought another slide to go with it so I can try my hand at milling the top for a Red Dot, installed a CarBo and Apex trigger system, bought a few different spring sets to trade out, and just made a couple of mods like removing the magazine safety.
I call it my Play pistol because I figure I can do anything I want to with it, in order to learn from it and if I totally screw it up, I'm only out $250 instead of $5-700 if it were a new pistol.