This subject is a bit of a legal and ethical minefield, depending heavily on where you live. If you’re looking into this, here’s a breakdown of what the landscape actually looks like right now: 1. The Legal Reality
Most people in this community don't "buy" the gun; they buy a (like an Ender 3 or Bamboo Lab) and download "CAD" files.
Sites like DEFCAD or Odysee host the blueprints. Note that the State Department has previously fought to keep these files offline under export control laws (ITAR).
These are often "single-shot" or low-durability items compared to traditional steel or aluminum firearms.