Steve,
They weren't as cheap back then as you think they were. Most of them sold for well over a hundred dollars back in the late 40s and 50s. To us that is nothing, but back then it was a small fortune. The machines were .... let us say .... less expensive. They were definitely not cheep.
That is a very nice machine. I wouldn't mind having it myself.
For today's market I'd agree that $30.00 for that machine in it's condition would be a good price.
Joe