What is it?
Google Opinion Rewards is an application for Android devices that allows you to earn Google Play Credits. These credits are simply just money that you can spend on anything in the store, whether it be an application from the store itself OR can be used for in-app purchases within applications such as games.
To earn these credits you simply answer the questions that the survey provides. Usually between 2 and 6 questions.
Simple as that.

How does it work?
You receive a notification when you have a survey. It's random, you can't choose when they appear and as far as i can tell, the only way to influence if you get the survey or not is to do more. Last year when i was doing more, i was getting one or two every week or so, since the new year i've not had many because i wasn't paying attention and swiped a few off because i didnt have time to do them at the time.

How much will you make?
You will be lucky to make more than £2 per month. Ive made 42p this month.
The pay out is based on your the survey you answer. I've personally made from 0.08p to 40p in a single survey.

How long do they take?
Seconds. Literally seconds. I don't think any of the surveys have lasted more than 30 seconds for me?

My Earnings, to show you it is a real thing -
Baring in mind that i've swapped phones a few times, and forgot to reinstall. Hence the gaps in earnings 😊
Spoiler (Click to View)

Example Survey
Spoiler (Click to View)