Billionaires' First Jobs: From Warren Buffett to Oprah Winfrey

— -- intro: Not all tycoons grow up with trust funds and silver spoons. Forbes' 33rd list of the 400 richest Americans includes self-made billionaires and a fair share of entrepreneurs who came from poor immigrant families. We thought the first jobs of these billionaires were noteworthy beginnings.

quicklist:title: Oprah Winfrey, #209category: Grocermedia: 25841386text: Before Oprah Winfrey had her mega daytime talk show and before she was the 209th richest American, she was a teenager working at the corner grocery store next to her father's barber shop in Nashville.

"I wasn't allowed to talk to the customers, and can you imagine for me?" she said, according to Oprah.com. "That was very, very, very hard."

But that changed when at age 16, she snagged a job that paid her to talk, according to Oprah.com. Radio station WVOL hired her to read the news on the air, which she loved and led to her first television gig.

quicklist:title: Charles Koch, #4category: consultant media: 25840555text: Businessman Charles Koch, 78, is Forbes' fourth richest American, tied with his younger brother David Koch, 74. His first job out of college was with Arthur D. Little consulting firm in Boston, Koch told the American Journal of Business in 2009.

quicklist:title: Elizabeth Holmes, #110category: Blood tester media: 25841000text: The list has 27 newcomers this year, including Elizabeth Holmes, 30, the youngest woman in the entire group of 400. Holmes founded Theranos, a Palo Alto blood diagnostics company, when she was a 19-year-old sophomore at Stanford University in the fall of 2003. She dropped out and is now worth $4.5 billion.

quicklist:title: Steve Ballmer, #18 category: Cake maker media: 25841521text: Okay, we would have loved to hear Steve Ballmer, the owner of the Los Angeles Clippers and former Microsoft CEO, was once a baker. The truth is almost as interesting: he was an assistant product manager for Duncan Hines' Moist & Easy cakes and brownies, according to USA Today. And his cubicle mate was Jeffrey Immelt, now CEO of General Electric.

Ballmer, worth $22.5 billion, re-entered Forbes' top 20 list after dropping out last year.

quicklist:title: Nick Woodman, #129category: E-commerce salesmanmedia: 25841472text: Nick Woodman had two startups before GoPro, which went public this year.

"The first, a website called EmpowerAll.com, attempted to sell electronic goods for no more than a $2 markup and was quickly shut down after failing to get off the ground," Forbes wrote.

Nicholas Woodman's fortune is now $3.9 billion, tripling from $1.3 billion last year, making the surf lover Forbes' largest percentage gainer this year.

quicklist:title: Jan Koum, #61category: Floor sweepermedia: 25841151text: Jan Koum, the CEO and co-founder of WhatsApp, immigrated with his mother to Mountain View, California, from Ukraine.

"She took up babysitting and Koum swept the floor of a grocery store to help make ends meet," Forbes wrote.

Now that WhatsApp was purchased by Facebook, Koum is worth $7.7 billion.

quicklist:title: Warren Buffett, #2category: Newspaper delivery boy media: 25844631text: When Warren Buffett's Berkshire Hathaway bought the Omaha World-Herald in 2011 he recalled his days as a delivery boy for the paper. At Berkshire's annual meeting that year, the billionaire, worth $67.8 billion today, challenged attendees to a paper toss.

quicklist:title: Bill Gates, #1category: Programmer media: 25840224text: Though little Billy may have done odd jobs as a kid in Washington state, his first corporate job was as computer programmer for aerospace firm TRW during his senior year in high school. Now he's worth $81.2 billion.

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