Low income earners may be able to get a Low Income Health Care Card that entitles you to a range of services for free or cheap. This includes reduced price pharmaceuticals (about $6), free emergency ambulance, free lenses and glasses frames, and free hearing aids. It can also help you to negotiate reduced prices for movie tickets, physiotherapy, chiropracty, acupuncture, etc.
To be considered a low income earner you need to be earning, on an 8 week average, less than $519 (as a single person with no dependents). This is not available to international students. If you currently receive a Centrelink payment you should already have a Health Care Card.