I think there are 4 popular ways to invest in cryptocurrency right now:
1. Mining. Typically, but it still actual after bitcoin price growth. Here you can start from 1500$, BUT! IMHO to start earn a good moneys per month, it should be at least 50.000$
2. long-terms investments in cryptocurrency. No words. a lot of money you need to start earn a lot.
3. Blockchain software development. Here you can start from scratch, because your clients will pay for your work in future. in average blochchain developer earn from 120k$/year.
4. build your own crypto exchange. very interesting way to