Ernie Garcia, Ryan Keeton, and Ben Huston

Garcia was working at an auto-financing company when he saw an opportunity in updating the car-buying experience that was "so big and so clear" he jumped. Three years after spinning out of DriveTime, Garcia, along with cofounders Huston and Keeton, have turned Carvana into a publicly traded company valued at more than $2 billion. This self-described "Amazon of cars" now has 1,375 employees and operates in 33 U.S. markets -- a fourfold increase in less than two years.