One way to immigrate is by starting or buying an US based business, but this seems to be more complicated than it sounds.

You need to fit a visa category, in this case most appropriate one being E-2 and are likely expected to invest a significant amount of money, albeit there is no required minimum. It's possible to get it with amounts lower than $100 000, but the safest bets are above $150 000, but this also depends on a case by case basis.

There are other criteria for qualification, aside from the investing amounts, which are just as important as money and which could disqualify an applicant even if (s)he has the money.

Processing time for these kinds of applications are normally 6 weeks to 6 months, but can be expedited for a fee of $1000 USD in which case you may get a response within 15 days.

Thanks to B.D. Ross from the FSP forum for the info. I've mostly paraphrased his post. Additional information or suggestions are welcome in comments or this topic or if distinct enough, as a separate tip.