Billionaire entrepreneur Richard Branson's commercial acumen was honed at a young age.

When he was just 14 years old, Branson started a student magazine and pitted two of the world's biggest business rivals against each other — Coca-Cola and Pepsi.

First, he would persuade the telephone operator to connect him to companies. "I was working out of the school phone box where you had to put money in. So instead of putting the money in, I just rang up the operator and said: 'I put the money in,'" he told CNBC's "The Brave Ones."

"The operator became my secretary and (would say): 'Hello, I have Mr Branson for you.' And I would go straight through to Coca-Cola or Pepsi without paying."

Branson soon realized that the best way to get competitors to advertise in his magazine was to tell them that their rival had agreed to do so.

He said: "I soon learned the art that if I let Coke know that Pepsi were definitely in, that Coke would then jump in. And my education started. It was an exciting time."

But the magazine eventually cost Branson his formal education, with the school principle giving him an ultimatum to quit the publication or quit high school. "I said: 'Thank you for that choice. I'm off to run the magazine,'" he told his teacher.

So Branson left high school, aged 15. His magazine made a profit, and soon after he founded Virgin.