About the only break open shotgun worth a darn in the $1000 area is a nice used Browning BT99. Other than that I would look at either the Rem 1100 trap, Rem 870 Trap or a Beretta AL391 trap although the later will usually be a higher price than $1000.
I have used my Browning 425 Sporting for trap on occasion but with the flat rib it gets to be a bit tough and you really have to stack your beads to make it work.
Most field guns shoot 50/50 or 50% above the line of sight and 50% below. A trap gun on the average will shot 70/30 or 70% above and 30% below so that you always have the clay in sight on a rising clay and unless your a really slow shooter and are shooting on the way down the 70/30 is what you need. That or take them right out of the house with a flat rib.
There are a lot of guns out that that will work for you but the Auto/pumps will be in the price range your talking of and will work great until you get good enough or interested enough to move up in price.