2. Dell: Michael Dell
In 1984, 19-year-old pre-med student Michael Dell dropped out of the University of Texas at Austin and founded "PCs Limited" with just $1,000. Operating out of a condo that year, the business sold between $50,000 and $80,000 in upgraded PCs, kits and add-on components. Later, the company would be renamed Dell.
Twenty-eight years later, Michael Dell is worth $15.9 billion, according to this year's Forbes billionaires list.