Welcome from Tennessee.
It all depends on which country and what part of the country you live in. I am sure I would do alot better back in New York or New Jersey.
A second had store generally sells things as is. When I buy certain machines, I know I will convert to hand cranks, I don't worry about electrical condition. I even buy when no controller is available.
I have paid hundreds too much. In a few instances it was a heart thing. I could tell the individual needed the money and I could afford it. In other cases I spoke too soon or did not know otherwise. I.E. my featherweight at the height of the market!
Don't kick yourself. Clean it up, convert it and enjoy it. I love my shuttle machines!