3d printer
As someone who has been in the 3d printing space for awhile, I am amazed at how cheap and featured the entry level printers are. For ~$150 you can get a printer with auto bed leveling and a magnetic bed. At $15/lb of filament, you only need a few projects to pay for itself.
For example, I printed the housing for a USB hub for a friend which is a clone for a ridiculously expensive one that fits Lovesac couches and he paid me $50. It cost ~$2 of filament and ended up printing a few more for others. That alone paid for the cost of the printer.
For anyone who is thinking about it, now is a great time to enter the hobby.