Here's a shotgun from the 1890s I had never heard of. The Burgess Folder, designed and built by Anthony Burgess. It was latched and hinged at the chamber and could be carried concealed in a holster. Popular Mechanics has an article about it and it was thrown over the transom by a friend.
It was a pump shotgun, with another twist. The pump action was built into the shoulder stock at the rear of the gun. He made a few rifles with the same mechanism in 30-30 and 45-70 as well as standard shotguns with the same pump mechanism.
I don't know what an original folder would actually sell for, I found prices from $2,000 to $12,000. I do know for most of us they are only something to read about.
Burgess was a designer of a number of firearms and developed a rifle that Colt built called the 1883 Burgess. It competed with Winchester's offerings and was superior enough that Winchester threatened to start making revolvers. Deals were made and production was shut down. Uberti make a replica in both rifle and carbine lengths that retails for around $1500.