Google Adwords will allow android user to try games for 10 minute, before you make a decision to download or not to download the game.
At Game Developers Conference (GDC), Google announced a new features in AdWords and Admod for Game developers to reach out to the right audience.
Try Mobile Games in Search Ads before downloading
Google recently introduced Trial Run Ads on the Google Display Network which allow users to stream your game from a display ad before they download.
When a user for a game on Google, they will see the option to “try now” in ad. These ads will appear on smartphone using wifi and will let the users to play up to 10 minute and they can then download the game if they want.

This will let developers drive highly qualified users who might remain engaged with the app eve after installing it.