I would think that $100 is on the really low side in poor condition.
Dad had a Mossberg 185 12ga bolt/poly choke when I was a kid,first shotgun I ever hunted with actually.I see them come up for sale every so often asking $150-$300....$200-$250 seems to be about avg?I only notice because I’ve often considered buying one when I see them for sale just for nostalgia.Ive taken that ol gun on the school bus then leaned it in the boot closet at school for the day and hunt my way way home on more then a few occasions,try doing that today,lol