The gun broker has one at auction with a starting bid of $450. Some were made by Pedersoli and are quality guns.
I have a Navy Arms 12Ga SXS made by Pedersoli and it is a high quality shotgun. But one must know that my shotgun was one of the first imported in to the US, it's a light 12 and has a walnut stock.
At $250, maybe you can talk them down a bit, I think it's a good buy. The major problem is getting the barrels to shoot in the same spot. You will wind up with one load that will put both ball into the same spot time after time. Will take some work but the rewards will be worth it. And if you decide to sell at a later date, showing how it shoots means you can ask more for it.
One last thing Dixie Gun Works sell the Pesersoli double rifle for $1100.
Tom F