Free: Contests & Raffles.
i'm very fond of older 870 wingmasters, especially the ones made in the late 70s-early '80s. they can be had very cheaply, the only drawback is that most have fixed barrels. however, they are steel shot safe, something that you can't say about a model 12. if you look around you can find screw in choke barrels, since most have been that way since the late '80s.
not a lot of "nice" pumps still offered besides the 870 wingmaster, ithaca 37, and browning BPS these days. the only ones still made in the US are the 870, 37 and mossberg 500/535/835.
870's are nice because they're so easy to take completely apart to clean. That is needed more often if you hunt ducks with it. If not, it's not really a big issue.The Browning BPS pretty much requires a gunsmith for a complete cleaning.I like the Ithaca 37's, nice and light, good chukar/pheasant gun.