Pokémon GO has generated an estimated $1.8bn in payments from players in 2 years

"Released two years ago today, Niantic’s Pokémon GO became an overnight sensation. While the fervor has subsided in the 24 months since that game-changing day, players worldwide continue to spend more than $2 million per day in their quest to catch those original Pokémon and the dozens that have been added since launch. This has led to the game reaching $1.8 billion in player spending, according to the latest Sensor Tower Store Intelligence estimates, having crossed the $1 billion milestone in January 2017."

Source:  Sensor Tower, 6th July 2018