The term "frugal billionaire" may seem like an oxymoron, but a small subset of the richest of the rich are well-known for their penny-pinching ways. While most people will never have that kind of money to throw around, everyone can take a page from the fiscally-responsible habits of these billionaires.

Warren Buffett

Warren Buffett, famed value investor, and Berkshire Hathaway (BRK.A, BRK.B) CEO, lives a modest lifestyle despite his net worth of around $108.9 billion (as of May 24, 2021). He purchased a five-bedroom house in Omaha in 1958 for $31,500 and has lived there ever since. Buffett spends little. He only recently relinquished his flip phone, and reportedly does not have a computer in his office.

Although he could afford a whole fleet of limousines to be at his beck and call, he prefers to drive himself and owns a Cadillac XTS, which he bought for $45,000 in 2014. When it comes to entertainment, the investment mogul shuns splashy parties and trips and spends his time playing bridge.

Mark Zuckerberg

Facebook (FB) CEO Mark Zuckerberg makes the list as one of the world's youngest billionaires. This Facebook creator had an estimated net worth of $116.7 billion (as of May 24, 2021). Almost all of his money is tied up in the social media company's equity.

By all accounts, Zuckerberg keeps his life low-key and spends up to 60 hours a week at Facebook's Palo Alto office. Zuckerberg chooses t-shirts and jeans over expensive tailored suits and sneakers and sandals over Italian leather loafers. His one big indulgence seems to be real estate, as he has a portfolio worth millions in properties, including homes in Palo Alto, Calif., and one in San Francisco's Mission District.

Carlos Slim Helu

Among the richest people in the world, Carlos Slim Helu has an estimated net worth of over $69.1 billion (as of May 24, 2021). He built his fortune in Mexico, where he owns more than many companies, including Telmex, the country's largest telephone service provider.

Slim shares many frugal traits with Warren Buffett, including living in a modest home and eschewing computers. Widowed since 1999, he spends most of his downtime at home with his children and grandchildren. In a country where security is often sketchy, he still chooses to drive himself wherever he goes. Although much more dandily dressed than Mark Zuckerberg, Slim purchases most of his clothing off the rack from one of the many retail franchises he owns.

John Cauldwell

John Caudwell, now retired from the British cellphone empire—Phones 4u—he built from scratch, owns many rich toys including a helicopter, yacht, and a car worth more than most people's homes. But when it comes to wasting money on everyday things, he's a stickler for saving.

Caudwell has an estimated net worth of $3.1 billion (as of May 24, 2021), but he cuts his own hair because he thinks barbershops are a waste of time and money. He buys his clothing off the rack at the British retailer Marks and Spencer. Before retirement, he would bike 14 miles to work each day rather than have someone drive him in his Bentley. Now, he bikes 40 miles every week to and from his favorite pub.

The Bottom Line

The uber-wealthy don't always live the high life, which helps them stay rich. The frugal billionaires listed above all came from modest means, where frugality was learned and practiced by their families. They carried these lessons with them in business and, one hopes, they will pass them on to their children.