In general, I don't think $100 is a lot to properly clean and service a vintage machine. If it's the same service your average shop is going to give it then it's high. If it's a full on cleaning like what most of us do, it's hours of work.
Before:
[ATTACH=CONFIG]521544[/ATTACH]
After:
[ATTACH=CONFIG]521545[/ATTACH]
And that's on top of tensioner rebuilds, clearing 40 years of thread from behind the bobbin base, etc.