Candy Crush Saga is a popular match-3 mobile game available on iOS, Android, and Facebook. Though initially free to play, the game generates billions in revenue through in-app purchases of extra lives, boosters, and other items. It has been the top grossing app in app stores and has made its developer, King, the fastest growing company in the UK through over $1 billion in annual sales and a potential IPO valuation of $5-7 billion.