Put a little money into an online savings account every week (and invest it elsewhere once you have more)
Enroll in your employer’s retirement plan and start investing 1%
Open an IRA and choose your own investments
Invest with a robo-advisor
Invest a small chunk of money in the stock market
Invest in real estate through a crowdfunding platform
Invest in mutual funds with low minimums (many companies waive the account minimum when you enroll in automatic investing)