That has the look of a Cornelius but it doesn't exactly match anything in the Soda Machine library. In any event, I would say the $100 price might be worth it if everything else is there. Of course, if he is asking $100, I would offer $50 and negotiate from there. Depending on the cooling system, it might not be an easy fix.
Plus, that is not a machine that you will want to put a lot of money into because in working condition it might only be worth $200 to $300 tops.
My 2 cents anyway.
Tim