If you "buy companies that are profitable and that have good balance sheets that pay dividends," says O'Leary, "you can sustain yourself through these massive corrections."
You can still do this, he says, "even if you only have $50 to invest or $100."
O'Leary, who owns O'Shares ETFs, recommends exchange traded funds because they are inexpensive and tax efficient. These ETFs are buckets of securities that track an index.
Similarly, other experts, including O'Leary's fellow Shark Mark Cuban and investor Warren Buffett, recommend index funds, which you can think of as low-risk, low-cost baskets of stocks.
You may also consider using an app that allows you to buy fractional shares, says O'Leary. His app, Beanstox, and others like Stockpile do this.