Self-made billionaire Mark Cuban shares the biggest misconception about becoming super rich

Entrepreneur and Dallas Mavericks owner Mark Cuban became a billionaire when he and his co-founders sold Broadcast.com to Yahoo for $5.7 billion in stock in 1999. He was 40 years old. Today, the 61-year-old is worth around $4.3 billion.

Hitting 10 figures "was surreal, just like it is now," Cuban told Alex Kennedy data-test=”Pullquote”>Everybody thinks that money changes you. And it can, in a lot of respects, but it doesn't have to.Mark Cubanself-made billionaire, owner of the Dallas Mavs

Figuring out how to navigate relationships after getting really rich did take some time, though, he said. "The hardest part, really, is just dealing with friends when it first happens, because they're the ones that aren't quite sure if you're going to be the same person, how you're going to act. Are you going to always pick up the check or only sometimes pick up the check?

"It's a little bit of an adjustment period, but your true friends stay your true friends."

Of course, coming into a lot of money, especially when you start with so little, will inevitably change some things, Cuban said. Money has allowed him more peace of mind and flexibility, for instance. "I'm lucky because I don't have to stress about bills, I don't have to worry if they're going to turn my lights off again and stuff like that, which I had to worry about in the past," he said. "I don't have to worry about money and I can set my own schedule."

Plus, he could afford to upgrade his lifestyle. The very first things he bought after becoming a billionaire were an impromptu party trip to Las Vegas, an island vacation and a mansion.

"No matter the scale, having more money than you did when you were broke changes you some," said Cuban. "But it doesn't have to change you a lot, and I think that's the biggest misconception."

Today, after being a member of the three comma club for more than two decades, his wealth still seems unbelievable to him: "Even today — every day — when it hits me, I'm just like, I just try to appreciate it and not take it for granted and not let it spoil me or my kids."