In brief
Android app developers can now generate and distribute promo codes to selected users. At the time of this January 2016 article, codes supported in-app payments but not subscriptions or redemption through the web store; each app could issue 500 codes per quarter, with no carryover of unused allocations.
Starting now, Android app developers can provide promo codes to selected users. Users who receive a promo code can enter it during the normal payment process in a game instead of paying to obtain an app's paid services, virtual currency, or similar items, or enter the code directly in the Google Play Store app. However, entering promo codes in the web version of the Google Play Store is not yet supported.
Helping developers promote their apps more quickly, promo codes have long been available in the App Store on Apple's iOS platform, but have been absent from the Google Play store in the Android ecosystem. That has finally changed: Android developers can now use Google's newly added promo code management feature.
Google announced on its developer website this new feature for in-app promotions. Android app developers can generate new promo codes in the Developer Console and distribute them to selected users through other channels, such as printed cards or email.
The introduction of promo codes means that Google's app developers can more easily market and promote their apps using these codes.
However, according to 9to5Google, a website that follows Google developments, Google's promo code management feature still has a number of limitations. For example, promo codes can only be used for in-app payments, while in-app subscription-based apps are not yet supported. In addition, each app can issue only 500 promo codes per quarter, and unused allocations cannot be carried over to the next quarter.
http://www.ithome.com.tw/news/103289