The whole Mirror World series by Alexey Osadchuk for 10$ only.

In Google Play:

October 7 - Mirror World 1: Project Daily Grind for 0,99$ -
https://goo.gl/FxFwM9

October 8 - Mirror World 2: The Citadel for 2,99$ -
https://goo.gl/euQN17

October 9 - Mirror World 3: The Way of the Outcast for 2,99$ - 
https://goo.gl/mm5Pgh

October 10 - Mirror World 4: Twilight Obelisk for 2,99$ - 
https://goo.gl/aFdynm