David Karp, founder and CEO of Tumblr. Rob Kim/Getty Images for Tumbl While some tech executives are quick to splurge on yachts and mega-mansions, others aren't so flashy with their riches.

Biz Stone, for example, says he's too embarrassed to drive anything more flashy than a dented Volkswagen Golf, while Sergey Brin likes to buy things in bulk at Costco.

We've rounded up 11 tech executives who have made millions or even billions with their companies yet have chosen lives of frugality and charity.