The big cost the 3-D equipment you have to purchase upfront.
But if you’ve already got a 3-D printer. Have at it!
https://ultimaker.com/learn/how-much-does-a-3d-printer-cost
I don’t think the ones under $400 would get the job done. Probably talking more like $1000-$1500.
You could make that investment up quickly at buy-backs! Think I’ll buy one.
A printed gun does not need to work. So a cheap 3d printer around $200 will work great. There is a lot of learnig to 3d printing, so do not expect to just buy a printer and earn money. But if they ever do this in my area, you can bet they will be buying my oddly shaped pieces of plastic.
Who knew these miscreants could master a 3-d printer...
I know of people printing all sorts of modern stuff that will hold up (glock, Hk, AR/AK etc clones) on $200 Creality Ender printers
Here’s a goo intro into this tech
https://twitter.com/printingguns