They know they could buy a decent printer for a couple hundred bucks, but for them that’s not the point. Some hackers are just as (if not more) interested in designing and building the machines ...

[Ziggurat29] had been playing around with infrared protocols, and realized he had a spare point-of-sale printer kicking around in his junk box ... mechanical adding machines often had them.

How one amazing YouTuber turned a 3D printer into an automated tattoo machine.