That's an easy question to answer, although the answer is not that specific: there are so many vintage pens from the 1960s and 1950s one can find, often for much less than US $ 100, including great stuff by Montblanc, like the 22x models. These have to be my absolute favourites because of their high quality, excellent performance and remarkably good condition. They're wonderful daily writers and a joy to use with all those great inks we're having by Diamine, R&K, KWZ and others. You have to be careful, though, and match the ink to the pen (not forgetting the paper).
I want perspective right now more than information on a specific pen. I'll check out some of the 22 series models, they sound interesting!