Under Regulation Crowdfunding, how much you can invest depends on whether you are an accredited or non-accredited investor.

Accredited Investors
Accredited investors are not subject to investment limits under Reg CF.
If you meet the SEC’s accredited investor criteria - such as high income, high net worth, or holding certain financial licenses - you may invest any amount you choose in Reg CF offerings.

Non-Accredited Investors (something like 90% of the US population) 
Non-accredited investors must follow SEC-imposed limits based on annual income and net worth:

If both your income and net worth are below $124,000:
You may invest up to the greater of $2,500 or 5% of the lesser of those two amounts.

If both your income and net worth are $124,000 or more:
You may invest up to 10% of the lesser of those two amounts,
capped at a maximum of $124,000 across all Reg CF investments in any 12-month period.

Summary
Accredited investors: No limits
Non-accredited investors: Limits apply based on income/net worth
Maximum for non-accredited investors: $124,000 per 12-month period, across all Reg CF offerings

If you're unsure whether you qualify as accredited or want help calculating your investment limit, most RegCF platforms have an online "calculator" available so you can do a quick check of your eligibility.