I guess I'm the only one suggesting why not to get it.
It was a certainly well made car 50 years ago, but there was nothing particularly special about a bottom end Mercedes sedan of that era. (4 on the column manuals are notoriously balky) To me, there should to be some connection beyond it being dirt cheap, having basic parts for the most part still available, and that it might draw a few curious looks. Do you have a connection to it, or is this just an impulse buy?
I could understand your wanting an old Caddy of that vintage as you've been a Caddy fan for years, or at least a Mercedes 190SL, which is sexy. That 190B is not a particularly sexy car IMHO.
Your call.