And won't stand up to regular Skeet shooting. They are guns for the guy who shoots a round of Trap or Skeet just before hunting season, and maybe a box or two during the season. Quite honesly, I'd be looking for a used 1100 Skeet, or a field model 1100 with a 26 or 28" RemChoke barrel, and throw an Improved Cylinder choke in it.
I've shot Skeet with a pump, an 870, and it is good practice for working that action fast, but if your just going to shoot Skeet, maybe join a league, a semi like the 1100 or Beretta a 3xx or a400 will be a better choice.
As far as O/U's they are better for Skeet, but the minimum to consider is a Browning Citori. These can be found under $1000 used, particularly 26" Skeet guns, The Beretta 6xx series are another good choice, but these two guns have very different handling chracteristics. Try to handle, or better yet shoot, both. You'll probably find one or the other fits you real well, and the other one not so much.
Sharp Dog. That 20 ga. Superposed isn't going to go for $405, and you know it.
Sneakshot, where are you in WI? If you are close to LaCrosse, Monsoor's has some good clays guns, and some are at good prices. If you are near Prarie Du Sac, check out Recob's Target Shop out. Again, good guns, good prices, and great service. There's always the 3 Cabela's in Prairie Du Chein, Sun Prairie, and Richfield, west to east. The gun libraries often have some good clays guns. Don't forget Scheel's in Eau Claire and Appleton.