Short-run CD duplication didn't become economic until the late 1990s. Until then, if you wanted just a few hundred copies you'd probably be selling cassette tapes. Though short-run vinyl pressing was also an option.
If you wanted to do it completely yourself, custom-length blank cassettes were easily available, you could use two recorders or a dual-cassette machine. Domestic high-speed dubbing machines were available, but quality was questionable for music. Or you could use a professional duplicating house which might record many 'stripes' onto wide-format tape then slit it. I used one shop that literally had a wall of domestic cassette machines wired up to record simultaneously. Then there were several options for printing labels and inserts, or printing direct to the cassette shell. One way or another, it was very possible to do a small or medium run at acceptable cost, and most bands and acts had cassette tapes for sale after the gig.
There was no need to get a 'label' or other publisher involved, for cassettes or, later, CDs. The pressing/duplicating businesses would happily take an order from anyone.
How did we make the recording? Well, back in the 1970s I was multi-tracking by bouncing between a couple of Revox reel-to-reel machines and then the PortaStudio came along, closely followed by affordable 8-track machines. And in 1993 Cubase Audio on the Atari Falcon came into the picture. But if you were performers rather than 'bedroom studio' songwriters, you'd still quite likely book some time in an 8-track studio. There were plenty around (even, I imagine, in St. Louis :-) and competition kept prices low. And, remember, we were performing already-rehearsed material, not using the studio as a writing aid. A few hours in a local studio, maybe coupled with a deal on pressing 100 disks or cassette tapes, was quite affordable.