9) Emma Chamberlain

After her YouTube popularity sky-rocketed, Emma Chamberlain, 22, dropped out of high school to focus on her internet career full-time.

With an estimated earning of $20 million, the social media star has expanded her brand beyond her YouTube channel, and has secured a fashion deal with Louis Vuitton and partnerships with the likes of Levi's, Cartier and Lancome.

As well as her brand deals, Emma founded the beverage company Chamberlain Coffee, which is stocked at Walmart.