Originally posted by RioRico AF primes in a headshot-portrait focal-length range generally aren't cheap. A less expensive alternative: a manual lens, and CIF (catch-in-focus). I use this sort of setup extensively for fairly dynamic shoots. It's easy to use supplemental flash with a PK-A mount lens. If using ambient or controlled light, a PK-M prime, or a screwmount lens with adapter, will do just fine, as long as the lens base or adapter are wide enough to cover the lens-mount contacts. (That's necessary for CIF.)
My lens-of-the-day today: An M42 Novoflex Noflexar 105/3.5 bellows-macro lens (US$27 shipped) on a Bellowscope (US$21 shipped) and wide-flange M42-PK adapter (US$5 shipped). That's a nice handy cheap lightweight macro / portrait / short-tele setup. I've been shooting bugs on flowers, still and moving people, street'scapes, etc. Cheap enlarger lenses with edge-to-edge flatfield sharpness (75-140mm range) on bellows are great for portraits and similar work.
My other less-expensive M42 favorites: Vivitar-Komine 90/2.8 macro. Meyer Trioplan 100/2.8. Super-Takumar 105/2.8. None of these cost me much. All produce quite good results. None require bellows!
If you *need* automation, spend money on an AF lens. If you *need* flash, get an AF or PK-A lens. If not, try exploring the possibilities of manual and bellows lenses. The results can be brilliantly good.
Your first comment that
"AF primes in a headshot-portrait focal-length range generally aren't cheap" is relative isn't it? From the gist of many of your threads, it sounds like you're just poor or you're just not prepared to spend a reasonable amount on a good modern AF lens, and that's probably why you strongly espouse cheap and dare I say archaic options because that's probably the only options available to you. There are a whole lot of benefits that come with with AF and automation which I believe is a popular choice for the vast majority of photographers. Ease of use and speed to allow the photographer to quickly focus and obtain exposure accurately on the subject rather than fiddling manually with a old gear is a huge advantage that tips the scales towards a lens like the DA 100mm WR.