Ruger is off & on making o/u & sxs shotguns. I used to have a Red Label O/U in 20 ga that shot well. Unfortunately is now resides in my son's gun safe. I don't think they make the sxs anymore. I really don't believe you are going to find a NEW o/u or sxs that is made in the USA in your price range.
There is nothing wrong with the foreign made guns, some are really good quality pieces. I shoot a 20 ga sxs that was imported from Spain by Stoeger many years ago. It is a Zephyr Upland King, 3" 20 ga, side lock with engraving and unbelievable wood. I've owned the gun 40 years or so and have shoot thousands of birds (Dove, Chukkar, Pheasant) with it and it has never failed me. I also shoot a Charles Daley Japanese made o/u in 3" 20 ga. Same thing with this gun. Both guns sell used for less than you want to spend.
If I was looking for one today, I would look for a good used one. Browning, SKB, Ruger, AYA are all brands that come to mind that have made wonderful shotguns and there should be tons of them on the used market. I would look on line a Cabelas Gun Room, Guns America and Gunbroker.com. Start checking out you local gunshops and don't forget you local Trap/skeet ranges.