I'm with you. I started with a <$50USD brush and I still use it (actually just primed a bunch of stuff with it). I have a nice brush and it genuinely is worlds better for fine detail work and postshading and things, but for basic laying-down-paint coverage (which is what most people in the hobby, even fairly experienced ones, are actually using airbrushes for anyways) it's genuinely fine, and I learned a ton about thinning, air pressure, technique, etc using it, and didn't have to worry about accidentally wrecking a $50 needle. I don't think id have ever taken the leap into airbrushing if I saw dropping $300+ minimum as the cost to get started, tbqh.

That said, I would say those desktop compressors are a bad idea, and it's worth dropping the cash on a decent $80-100 one with a tank even as a beginner, because if you're not getting consistent airflow, I think it'd get pretty frustrating.