1. Blogging + Monetizing your blog with ads ( google ) , affiliate links, banner ads.
2. Offering a service at Fiverr
3. By Doing Freelance Jobs at Freelancers
4. Creating Awesome Videos on Youtube + Signing up for Google Adsense ads
5. By Creating Courses and Charging for them at Udemy
6. Writing an e-book and self publishing it with Pothi
7. If you are creative print designs, drawings or photos created by you on items like coffee cups, t-shirts, bags etc. and then sell them at Zazzle
8. If you are programmer/Designer Create and sell website themes and templates at ThemeForest
9. If you are a photographer and can click great pictures , sell your images online at Shutterstock
10. Learn and do Stock/forex trading . [teach me too once you learn ]
The Web is flooded with ways to Earn Online from Internet.
You can do any of the above listed , but these won't make you a Billionaire. For that you have to come up with revolutionary ideas , be creative, innovative and learn a lot. Read good books, meet great people, attend seminars.