Before Mark Cuban was a billionaire, he was a penny pincher. The “Shark Tank” investor embraced frugal spending habits, like driving inexpensive cars and utilizing grocery shopping hacks to trim food costs, as a young adult while he . Even now, there are certain aspects of luxury spending Cuban shies away from, as he once told he would still be happy if he was worth a tenth of his current net worth.

Let’s take a look back at some of Cuban’s most memorable frugal habits and how they helped him . Earning passive income doesn't need to be difficult. Up until age 25, Cuban owned and drove cheap cars — and we mean dirt cheap vehicles.

In an interview with , he said none of these cars cost more than $200. One of his cars, a Fiat X1/9, even had a hole in the floorboard. And according to a post on his blog, the car burned a quart of oil every week that Cuban couldn’t afford.

Cuban’s decision to drive inexpensive cars was made to save money so he could focus on being able to retire. Early in his career, he read “Cashing in on the American Dream: How to Retire at 35” by Paul Terhorst. The premise said you could retire if you found ways to live on just $50 a day and if you were disciplined in the ways you spent and saved your money.

Early in his career, one of Cuban’s key frugality habits was living like a student. When he was 24, he lived in a three-bedroom apartment in Dallas with five other roommates. “I didn’t have my own bedroom,” he said in the Blog Maver.