If you’re willing to fill in a survey or two in exchange for credit in Google Play, then Google Opinion Rewards is for you. The app is now available in Australia, as well as Canada and the UK.
It’s a fairly simple process, download the App and sign-in using your Google account. You’re taken through an initial setup process and sample survey to get you started. Once Google has a survey to send to you, you will receive a notification in your Notification Pane and you simply tap on it to start the process.
If you haven’t got any surveys to answer, you simply see your current Google Play Credit balance. It’s a pretty good system if you want to get some credit for next to no work. Try it out.