Earn Google Play Store Credit With This Google App – Google opinion rewards
This is app created by google developer team where you can give survey answers to google surveys in this app. After installing you will get notifications if google sent you some surveys to complete. After they will credit upto 65 rupees or 1$ for 1 survey. You can use this credit to buy apps in google play store.
Till now 5 lakhs people got downloaded and using this app and average rating got for this app till now was 4/5.