Everyone knows that financial gurus can do very well for themselves, but what about experts in other industries? People have made their fortunes with all sorts of ventures, from apparel to tech and even to fried chicken! With a good idea, lots of hard work, and a tiny bit of luck, self-made billionaires work their way to success. These four billionaires started out with nothing and worked up to where they are today.

1. Ken Fisher

Industry: Finance

Estimated Net Worth: $4.1 Billion

In the summer of 1964, 13-year-old Ken Fisher earned only $1.20 an hour picking fruit and fertilizing. From those humble beginnings, Fisher founded Fisher Investments in 1979 with only $250. He is now the executive chairman and co-chief investment officer of the firm, which serves high net worth institutional and private clients across the globe. He has written 11 books, 4 of which are national bestsellers. He has also written for USA Today, the Financial Times, Forbes, and several other international publications.

2. Meg Whitman

Industry: Technology/eCommerce

Estimated Net Worth: $3.3 Billion

Meg Whitman initially wanted to be a doctor and went to Princeton University to study medicine, but after only one summer of selling ads for Princeton’s magazine, she switched her major to economics and went on to earn her MBA from Harvard. From there, she worked in marketing at Procter and Gamble. She climbed her way up the corporate ladder and was responsible for bringing the UK show Teletubbies to the U.S. She moved into more corporate leadership roles and has served as the CEO of eBay, Hewlett-Packard, and now Quibi.

3. Sara Blakely

Industry: Apparel

Estimated Net Worth: $1.2 Billion

In 2012, Sara Blakely was named the youngest self-made female billionaire, and she got there by first selling fax machines door-to-door. After seven years of getting doors slammed in her face and facing constant rejection, she came up with the idea for Spanx. In hopes of looking better in her fitted pants, she cut out the feet of a pair of pantyhose to get the benefit of the control top while still being able to wear the sandals she wanted. With the birth of Spanx, she worked hard in production and design and created a worldwide brand.

4. Jack Cowin

Industry: Food

Estimated Net Worth: $1.7 Billion

Born in Windsor, Ontario, Jack Cowin started out as an insurance salesman before deciding to visit Australia to look for potential business opportunities. Long lines that stretched out of takeaway restaurants caught his eye right away. That convinced him that fast food would do well in the Land Down Under. From there, Cowin opened ten KFC franchises in Australia, followed by Hungry Jack’s, the Australian franchise of Burger King. His company, Competitive Foods Australia, still owns and runs those stores. He also owns Consolidated Foods, which exports meat throughout the world.

Going from working a boring, dead-end job to being a billionaire is possible. These four self-made billionaires show that with a good idea and some hard work, you can make a name for yourself.