With a round ball effective range was probably about 60 yards or so, quite adequate in dense woodlands. With shot they would perform about the same as a modern shotgun with a cylinder bore (While I do believe that slight chokes had been introduced by the mid 19th century, the probable date of those guns, I'm not sure if a plain utility shotgun like those would have been choked, though).
They are both simple utility shotguns, probably used by farmers for pest control, occasional small game hunting, and possibly teaching the next generation the basics of gun-handling. Not the least bit glamorous, but important nevertheless.
For what it is worth, I paid about $225 for a European shotgun of comparable age that I found at the local fleamarket. Mine looks pretty decent from a distance but has probably been refinished, had spurious Confederate marks carved, and been subjected to some poorly done "repairs," which make it worthless as a collector's item. I bought it mostly as a study piece and because it had a wooden triggerguard, something not seen in US made guns, and only afterwards realized that it was partially made with recycled parts from around 1750, which makes it much more interesting to me. I'm happy with it, but I doubt I could sell it for more than I paid.
So I think it depends greatly on who you are selling it to, but I don't think that you'd ever get much more than $150 or so.
