What small business can one start with relatively low initial investment (e.g 2000-20.000 $) and low domain specific knowledge, but decent general engineering knowledge ? I'm thinking specialized production machinery, e.g CNC, 3D printer, etc. to  mass produce / custom produce common / custom tools / products of relative simplicity but high enough demand (e.g cotton swabs, PCBs, as some examples that come to mind).On a more philosophical note, I observe that:
- we are flooded by products, information, ads, etc, a seemingly abundance of everything.
- production becomes more centralized (due to complexity)
- individuals are more and more limited in their ability to self sustain (consequence of the above)
- anxiety, depression, agression tends to increase (because of above). More so now, amplified by current pandemic and restrictions. Also, as a sidenote, the pandemic showed as we are not optimally organized (too centralized everything as apposed to more geographically and socially distributed)In that note, what self sustainable businesses would you think are good to exist more of, to the benefit of the individual and the society as a whole? And what are your thoughts and advices on getting there, one step at a time?