A guy under a YT username 1kreature started developing his own 3d printed N/CO2 laser tube. He has achieved some great results! Soon we can print some cool laZors!
... and here is more successful ignition with better vacuum:
He still has not published his files, but he is still developing the project. Sure, it will take some time and effort to perfect it and you will need some experience in building it but did I mention how cool lasers are!?
If you want to learn more about build a CO2 laser by yourself check out this link: