My 3d printer(s). I bought my first one used for $100 ~10 years ago and offered to print a small model for someone's college capstone project. People learned I had a printer and started coming to me for all sorts of small things. I would only charge for substantial jobs but people would end up paying me anyway. I quickly got a resin printer and started selling miniatures for friends. I eventually got contacted by one of the major manufacturers who would send me return units and replacement parts so I could repair and tell them what was broken, if anything, then I could keep or sell them.


Everything I have done with 3d printing has been subsidized by side jobs. It's a super fun hobby because 3d printing sits at the nexus point of basically every other hobby. I have done jobs for people building rat rods, model trains, cosplay, interior designers, hydroponics, brewing, architects, drones, and more.