Hi JulianK, the level of money required would depend on your type of work and where you wanted to live.
At an extreme basic wage of $500 per week, rent can be had for $180-200.
Tax is minimal on a low income, rises at a higher bracket. Low income earners are covered by the health care system , public schooling is also minimal. You would have to check what aussie newcomers are entitled to but from what I have heard the US has far more of a user pays system.