Jim Koch

Self-made billionaire and founder of The Boston Beer Co. Jim Koch also refuses to spring for expensive plane tickets. As Business Insider reports, he always flies coach. And he makes sure his employees join him in the cheap seats, including executives.

"On those long trips to Munich" for beer-ingredient research, "the upgrade from coach to first class is an extra $5,000," he writes in his memoir, "Quench Your Own Thirst."

"I can't make the math work — the average person at Boston Beer makes $55,000 a year. How can I justify paying over a month's salary for a first-class ticket? Is having me get a little more legroom and a better meal really more valuable to the company than what the average person contributes every month? I've never believed that."