20. Bobby “B.o.B” Simmons, Jr., $5 million (tie)
The 22-year-old rapper-singer-songwriter burst onto the scene in 2010 with the smash hit “Nothin’ on You,” featuring Bruno Mars. The duo performed the song at the Grammys, helping to fuel sales of B.o.B’s first album, The Adventures of Bobby Ray. Touring, guest appearances and a viral Adidas commercial boosted him to his Cash Kings debut.