Billionaire Mark Cuban has always been careful with his money.
When he was younger, "I did things like having five roommates and living off of macaroni and cheese, and I was very, very frugal," he tells Money. "I had the worst possible car — those types of things."
Even after earning millions, and eventually billions, the entrepreneur has continued to play it safe: "I've lived in the same house for 18 years and still have the same cars."
When Cuban became a billionaire back in the late '90s, however, he did make one splurge purchase, and he still stands by it.