Its only worth what someone would pay for it.
If it has all its parts, I'd say at least $150-$200. The thing with older wheels is parts are hard to come by. Manufacturing parts for a wheel isn't impossible, but it does get expensive. A few years ago, I spent $60 for a woodworker to make 2 bobbins for me for an antique (late 1700's) Irish Saxon wheel.
I'd be interested in seeing photos. I'm not in the market for another wheel (there are currently 5 in my flock) but I love looking at older wheels.