I have an original 81a myself.
I bought my machine 5 years ago for $2,500. The machine had lived indoors it's entire life and was in very good/excellent original condition.
Perhaps I overpaid at that time, but it didn't matter to me. I could afford it and it was exactly what I wanted; an original, unrestored Vendo 81.
I have no clue on what the current value is on an 81A. I
Good luck.