First, You can become a billionaire by buying stock.
Secondly, Invest in Real Estate.
This involves buying a property in your name. It is considered to be the fastest way to becoming a billionaire as the owner gets to have all the profit money earned.
Thirdly, Forex or CFD trading is a risky business that works largely on the guessing game. CFD, shortened for contract for difference, is all about guessing if the prices of a specific item would go up or down, and you win or lose money based on it.
Fourthly, invest in Cryptocurrency. Digital currency is gaining immensely.