[raven393]

If you really want to bootstrap it, start with toy/hobby rockets and drones and slowly work up. Alter the services you offer as you go eg: aerial photography, weather monitoring, engines etc etc till eventually you're launching small sattelites and stuff

It's the kind of thing that'd probably take decades before you were realistically even beginning to look at space though

[chasd00]

the amateur rocketry crowd has had large solid rocket motors for a while now but bi-propellent motors (event the most simple designs) are very very rare. If you could design one in the N impulse range and price it at < $2500 they'd sell like hot cakes. Then you could scale up the design to a bit more powerful and sell it to universities at around 10k a pop. The service contract to keep them running would be worth a lot o f money too. Eventually, you'd be able to sell a Karman line capable kit and that would sell like hotcakes to both the amateur rocketry and university crowd.

There's a group on youtube working on nitrous oxide/methanol engine for hobbyists now. I think they're headed in the right direction although I would have done the combustion chamber differently. https://www.youtube.com/channel/UCEkE_gf1VxBngLugexHz2KQ