A shotgun for under 1000 would usually mean a pump or used gas gun. You might check CDNN to see what they have - now and again they get Lanbers and even some Browning field models for somewhere close to that amount.
A SxS under 1000 would mean a Huglu-made CZ - which can be or miss quality wise. For a few bucks more, look at the S&W Elite Gold, now called the Dickinson from Cabela's. WHile Turkish, they are made to a mucher standard than the current Huglu CZ's with better balance, triggers, wood to metal fit, etc.
I own the S&W version - it was a good buy at original price of $2500 but it was an absolute steal when discontinued for $1200