Do you have some free time on your hands? You can do something meaningful and it won't cost you anything but a little bit of your time. Most studies that ask for volunteers do offer some kind of "thank you" ranging from straight-up cash, to vouchers, to entering a draw for one or more rewards. But don't do it just for the payoff. Do it to make a meaningful contribution to your society.

image courtesy of unisa.edu.au
There's no point in sitting at home with the sniffles feeling useless this winter! There are plenty of opportunities to participate in research through online surveys, helping universities with valuable information about how real people (of all ages, occupations and backgrounds) actually live, think and behave. Surveys that contribute significantly to research about the real human condition start from about 10 - 20 minutes. There are longer ones, but each research project will tell you before you start approximately how much time their survey will take. And, of course, as with any research participation, you can opt-out at any time.
You can look for research participation opportunities at any of the many
Australian universities. Or you can check out the research projects currently seeking participants at your favourite uni. Here are
Flinders University,
Adelaide Uni and
Uni SA listings if you're particularly keen to help South Australian research.

image courtesy of adelaide.edu.au
Things to look for include, what the research is about, what participants are asked to do, your rights (to ask questions, to withdraw at any time, to receive debriefing afterwards, to receive a summary of the research findings when the study is complete) how much of your time it will take, and if you fit the criteria! Also, expect to see contact details for the researchers in case you have questions or issues to discuss. Where a university is working collaboratively with another institution this will be clearly stated up-front when you read about the research project.

image courtesy of flinders.edu.au
Here are just a couple of online surveys I've found that almost anyone over 18 who speaks/reads English can take part in:
Flinders University, in conjunction with University of Helsinki, are looking at
determination, courage and resoluteness (Sisu)Uni SA are studying public
perception of Protein Supplements.
If you have a little more time and want to get out of the house, there are also lots of opportunities to take part in research where you will be asked to attend the research venue (usually the University running the research). A few you might find interesting are:
Flinders University,
Food Cravings study (scroll down the list).
Adelaide University,
Imagination and ESP (scroll down the list, you'll see it.)
Uni SA,
Breakfast Study, if you're happy to have a couple of free breakfasts and lunches at Uni!
If you take part in current, cutting edge research with our internationally renowned Universities, you can't complain that no one ever asked you and where do they get this stuff anyway! Contribute to knowledge. Contribute to the future. (And no one is asking you for money! How's that!)