Billionaire John Paul DeJoria says the smartest thing he's ever done with his money is a habit he started at age 6

Billionaire John Paul DeJoria is the epitome of a rags-to-riches success story.

Before building Patrón tequila and John Paul Mitchell Systems hair products, which led to an estimated $3.1 billion fortune, DeJoria spent time in a street gang as a boy, lived out of his car for a while, and was fired more than once.

He even resorted to collecting discarded bottles to cash in at grocery stores in order to support his 20-some self and 3-year-old son.

Born into a poor immigrant household, he was cash-strapped from day one, but if you ask him about the smartest thing he's ever done with his money, he'll tell you about a time when he was just six years old and donated money for the first time:

The very first experience I had with money was during the holidays. I was very young, about five or six I believe, and my mother handed over 10 cents to both me and my brother. She asked us to place it into the Salvation Army ringing box.

I remember at the time that 10 cents seemed like a lot of money - and we didn't have much back then. However, I quickly learned what it felt like to give to others and to those who might need it a little more than you. It was an incredible feeling and life changing experience.

Today, DeJoria has a lot more than 10 cents to give, yet he still feels just as fulfilled helping others in need as he did that one holiday season about 65 years ago.

"If I had to pick one moment that truly felt amazing, it was when I helped Mobile Loaves & Fishes build gardens and homes for those in need of shelter and food," he writes on Business Insider. "I helped give someone a place to live, a garden to work at, and another chance at life. To this day, that's where I feel most fulfilled in life. It's having the ability and resources to provide more resources to those in need."

READ MORE: 9 successful people share the smartest thing they've ever done with their money »