Begin with the MSRP, which I believe to be $1,425. Then see what the street price is for a new one. I didn't see a 28 GA on Guns International, but a new 12 with an asking price of $1200. Asking price is one thing, but can you find out what they are selling for on Guns International? $850 doesn't sound unfair to me. That is 29% off the street price and you say it is mint condition.