There is also a wide range of choices and prices- I assume the $350- 400 guns aren't probably that good and the $1,500 plus guns are likely all pretty good. What about some of the in between choices? Any recommendations?
Check CDNN and Bud's along with other sites and you should be able to find a nice Beretta or Browning O/U, or possibly a SKB for your price range. With proper care in a marine environment, they'll last you a lifetime of hunting