Watching to see the suggestions of others. I have an old Smith Corona and saw on eBay they were from about $50 to $150. I am ready to get rid of it, if LOML doesn't find out.
I had a friend shed some light to me - on some things like this about 20 years ago, and he has been a prophet of sorts. So many of our parents and aunts and uncles who grew up during the depression acquired al sorts of what-not things and home use objects after the depression, and the early baby boomers have done similar. If you go to a bunch of flea markets you can find these thing flooding the flea markets today and not as rare as one would think.
That takes me to "Pawn Stars": in the past year, someone took in one of those 1 gallon butter churns. I think the pawn stars paid $300 or so because it was both unique and from a by-gone era. Shucks, They can be had in rural flea markets across AL, MS, AR, TN for $20 - $30. Of course some places that are geared towards unsuspecting tourists sell them for $50+, but no where near what the Pawn Stars paid. I have two my mom had.