Question about Google Maps and Augmented Reality Application

Has anyone looked into or is developing an AR app using Google Maps? I am designing an AR application along the lines of Pokemon GO. It will have a user using their mobile phone and walking in their area encountering NPC's and fighting, earning credits to be used to buy weapons etc. I am a little confused on what Google Maps API's I will require. In addition, it seems like once the monthly free limits are reached, then I am expected to pay additional costs. How does the game make me any money if i am responsible for additional charges for map usage?