To join the program, launch the Play Store app on your Android smartphone and then tap the three lines icon located inside the search bar at the top interface. You'll then see a menu item called "Play Points." The program is free to join, and you can earn points on everything you buy from the Play Store, including in-app purchases and subscriptions. You can earn additional points by downloading a rotating list of featured apps each week, as well as taking advantage of weekly promotions.
Once you have some points, you can redeem them for Play Store credit, in addition to in-app purchases -- which might make that secret Candy Crush Saga addiction a tad more affordable. Lastly, you can donate the points to a variety of nonprofits.
With each dollar spent, you also move closer to a higher rewards tier. There are four tiers in total. Each one comes with additional perks. The most notable bonus is that you earn more points per dollar spent than in the previous category. With the platinum tier, for instance, you get 1.4 points per dollar compared to one point per dollar in the bronze tier. The catch is that you have to maintain a certain level of spending to stay in a specific category.
If you want to earn additional Play Store credits, you can also download Google's longstanding Opinion Rewards app, which lets you earn app rewards by giving your two cents on a variety of topics.