Google has allowed developers to temporarily reduce to zero the price of apps in the Play Store
Google changed the policy regarding paid apps in the Play store. Previously, developers who have placed their application for a fee, could, if desired, to make them free, but this change was irreversible.
Temporarily, you can only reduce the price to a minimum. Now Google has allowed developers to make their paid FOR free for a short period of time.
To make the app free for a period of one to eight days. And to it developers can apply indefinitely. The only condition is that between the sales of a single application must take place not less than 30 days including the date of commencement and completion. Developers can use this opportunity to attract more attention to her.