Early estimates were $5. When contacted, the maker said the cost was $3 per pistol.
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.