The “Promotions” tab has appeared in the Google Play developer console. Android developers will now be able to provide users with free access to applications or IAP using promo codes.
The function has limitations. During the quarter, you will be able to distribute no more than 500 access codes per application. After the deadline has expired, the developer will have the opportunity to distribute the same amount. At the same time, users will lose access to promo codes that were not used during the last quarter.
Developers will be able to view and change the conditions for the distribution of codes directly during the promotion – through the console.
A detailed description of the new function is available at the link.
A source: https://support.google.com