Google Opinion Rewards
Google Opinion Rewards is a rewards-based program developed by Google. It was initially launched as a survey mobile app for Android and iOS developed by Google. The app allows users to answer surveys and earn rewards. On Android, users earn Google Play credits which can be redeemed by buying paid apps from Google Play. On iOS, users are paid via PayPal. Users in the available countries who are over 18 years old are eligible.
Read article on Wikipedia