Google is now rolling out a system to offer Google Play credits for your opinions. Last year Google launched, Google Consumer Surveys (GCS). GCS is survey tool used to ask for your opinion as you try to access premium content for news sites. It acts very similar to the way Facebook marketers used to use like gates. If you didn't notice, a like-gate is/was a small hurdle that is placed in the way of content, you can see the article or signup for the contest once you click 'like'. On Facebook the like gate was away for brand pages to increase the amount of likes their page had. In the case of Google Consumer Surveys it is a way to get people to complete their survey before people can view full articles or other content. Research companies, large brands and anyone that wants a fast way to survey people uses GCS.
Expanding their survey population beyond the desktop, Google has built Google Opinion Rewards. This system uses an app (Andriod only for now) that users install on their phone. The application will then notify users when there is a survey available for them. What does Google get? Anywhere from $1.10 to $3.50 per completed survey. What's in it for the person completing the survey? $1.00 in Google Play credit that can be used to buy songs, apps, books, or games.