On July 4, Mark Cuban tweeted that it was the anniversary of the date he left Indiana University in Bloomington "with $60, hole in my floorboard, case of oil in the trunk & a floor to sleep on in Dallas."
A few days later, Cuban, then 23, moved in to a $600-a-month three-bedroom apartment with five other guys.
"Literally, Cuban landed on our doorstep flat-busted broke," Greg Schipper, one of those roommates, tells the Dallas News.
Besides having no money, Cuban, who his roommates nicknamed "Slobbins," according to the Dallas News, had student loan debt.
So how did Cuban become the billionaire he is today?
"I had nothing. So I had nothing to lose, right? It was all about going for it," says Cuban.
In Dallas, Cuban got a job at a company called Your Business Software. "I sold software and I got fired," says Cuban, on Arianna Huffington's The Thrive Global Podcast.
"I got fired because he wanted me to open up the store. It was a software retail store — I had to sweep the floor, make sure the windows were clean, make sure the store was open on time.
"I had a big deal I wanted to close. And I thought, 'Okay, I'm gonna let Michael (his name was Michael) know that I've got everything taken care of, someone's watching my shift if you will, and I'm gonna go pick up a $10,000 check,'" he tells Thrive Global.
"I figured when I came back he'd be thrilled to death, right? Fired me on the spot," says Cuban.
"I had quit or been fired from three straight jobs," says Cuban on ABC's "Shark Tank," where he is a judge.
But the experience was not wasted.
Cuban had never been into technology: "I took one computer class and cheated at it," he says.
"But when I got one of my first jobs out of school using technology, it was like, wait, I love this. I've taught myself the program, I could go seven hours, eight hours without taking a break thinking it was 10 minutes because I was concentrating so hard and so excited and really loved it. And that's when I realized that I can be really, really good at technology."
So Cuban started his own business, MicroSolutions. He sold it to CompuServe for $6 million in 1990.
Five years later, Cuban and a pal, Todd Wagner, created an online streaming audio service called Broadcast.com so they could listen to Hoosiers games in Texas. Yahoo acquired the business in 1999 for $5.7 billion in stock.
Cuban now owns the Dallas Mavericks basketball team, is an investor and stars on "Shark Tank."
Even as a billionaire, Cuban still stays on top of what's happening in the tech industry. He's currently taking a Python computer programming class and reading "Machine Learning for Dummies."
But these days, he doesn't have the same fire as when he only had that $60 in his pocket.
"The good news of having had the level of success I have is obvious, but the bad side is I kinda lost that piss and vinegar," says Cuban. "I can think of 50 businesses I could start right now ... but I don't want to give up time at home and all that. So that's kind of the trade off."
Don't miss:
The one book that changed Oprah Winfrey's life and business
Apple co-founder Steve Wozniak's formula for happiness doesn't have anything to do with money
Like this story? Like CNBC Make It on Facebook.
This story has been revised to correct the amount at which Yahoo acquired Broadcast.com.