In the late 80's I got one at the local hardware store. I'm sure it was under $100. Now I saw one at $1400.00..!!!!!!!
I could adapt one but the itch to build one is setting in. The $50 electronic ones are just a Chinese controller, no servo or sensor. But I'd rather do my programming with a lathe and welder.
Air might be an option but the ball thing would be the checkers.