Pokemon GO is the first Pokemon game on Smartphones that lets the player capture and fight Pokemon. It has proven to be extremely successful for publisher Nintendo. Since the game is basically free-to-play with microtransactions in place, it requires the player to either work hard or use real life money to purchase in-game rewards.
If you want to easily gain coins that you can use to purchase items in the game, you have to join a Pokemon gym as a trainer. If you are part of a Team that controls the gym, you simply have to leave your Pokemon there in order to get coins every day. These Pokemon will be used as a defense for the Gym and the player is rewarded in the form of free coins daily.
This method can yield up to 10 coins after each 20 hours in the form of daily bonuses and this can be done for 10 gyms to get 100 coins everyday. Of course, this is not a simple method and requires a team that is in control of the gym as well as ignores any additional issues like the rival team attacking and taking control of the gym, but it is still a better method than spending real life money on microtransactions.
Pokemon Go is available now for the iOS and Android. It was developed by Niantic Labs and published by Nintendo.