1. Buy a kit.
2. Buy a mechanical kit and an electronics package.
3. Build from scratch
4. Buy out of state
5. Buy an open source machine and flash the firmware
6. Buy your fucking gun in an alley (way easier, and maybe cheaper.)
7. Design and distribute stls that have parts that may be interpreted by whatever brain dead software is going to watch out for files, and print in two batches, say, something that may look like a lower, and then an upper, for a a nerf gun, for example, to glut the system.

The list goes on…