I have been seeing Remington 870 Police shotguns going in the $299 range...Wingmasters, Police Magnums, 870P...usually carried much and shot much less...if you trust the seller and the one you look at isn't too beat up, that's not bad (at least around Chicagoland...)
Should have a couple nicer parts than a garden variety 870 Express and the action is probably polished up nicely from being racked so much...
Bill