Welcome to GH!! I'm sure there are many here who would love to hear your response to this question - What is the best/cheapest/easiest method to make our own caps at home
Kind of a tough one, maybe there is no right answer. I guess it depends on what criteria you will use to evaluate best, easiest and make.
You could prob setup a scaled-down version of SP for +/- $750K which would prob be best but not easy.
FDM/3d printers are becoming popular but there are so many online services offering that on a contract basis it seems hard to justify buying one – plus I don’t think the 3d printer version of keycaps would really suit anyone’s taste.
If you just want to modify existing caps then a pad printer + a CNC router or CNC engraver would be an option.
A few weeks back a guy posted pictures of some CNC wood keys, they looked pretty awesome.