Up till now promo codes were not available for Android apps the way they are on iOS apps. As you might be aware, promote codes are given by businesses to encourage people to try out their products and services either for free or at discounted rates. But then you may think, what’s the difference between a free trial and using something via a promo code? After all, there are many Android apps available that you can use for free for some time and then later on there is a feature of “in app” purchases that can be used to avail the premium version. The initial information regarding the Google Play Store letting app developers offer promo codes has appeared on this Android Forums thread.
Promo codes most probably will be used by Android apps developers to encourage people to try out the premium versions of their apps without having to pay for them or without having to pay the full price. There is a restriction though; an android apps company can offer maximum 500 promo codes per quarter and these codes cannot be carried over to the next quarter. They will also need to have an expiration date.
In a page titled Create promotions Google has explained to Android apps developers how they can get their apps ready to use the promo codes, what other restrictions and how they can promote their apps using the codes.