Really, any shotgun will do. Decide whether you want a semi auto or a pump, 12 gauge or 20 gauge, then go from there. I suggest a 12, so you can kill geese more effectively as well (I know a 20 can kill geese fine, but I prefer 12). Handle a bunch of them, see which shoulders best and is the most comfortable. Also, take into consideration whether you want to shoot 3" shells or get a gun that can handle 3.5". Plenty of guns in your price range.
Or, you could always go with one of these:
