I'll add my 2 cents first off price is very difficult without having in my hands to inspect. They are going up in price like everything else related to firearms today. Years ago, that would have been in an old whiskey barrel setting in the corner of the locale gun shop with several others for about $30.00. About 5 years ago I picked one up that was in very nice condition with new nibbles installed and locks tuned ready to hunt with for $350 including shipping on GB. Last month picked up a 14 ga. that needed new nibbles and bores cleaned (polished) English gun at an online estate sale for $130 plus 50 to ship. Recently I picked up a 12ga with 30" barrels Belgium gun not as rough as yours in California for $ 280 including shipping to me in Virginia. I say yours is around $200 to the right guy. There only worth what someone is willing to pay.
