Australia is the most expensive Anglo-saxon country by far and 1 of the most expensive countries in the world, so you'll have to bring lots of money. Or a tent and not as much.
Average property price is A$585k (US$530k) vs US $175k vs GB pound 143k (US$ 230)... our interest rates are also the highest... so expect rent to cripple you (A$2000-3000 a month in the city (Sydney)). You even have to bid up places (pay more than the asking rent) cos Howard/Rudd invited the world in and didn't build the infrastructure to accomodate the influx.
Food is also more expensive than any other Anglo-saxon country... every time I go to Whoolies I spend A$100 for 2 days food (2 people)... And don't even think about bring supplies in, cos customs will analy probe you and confiscate anything they want and then charge u for the pleasure.
Kites, again most expensive.
Parking again most expensive... and allow for multiple fines (not sure about WA, but in NSW/Vic just open your wallet & bend over any time u see a Ranger/Cop).
++ Road tolls, speed/red light/hidden/funny/plane/chopper/car cams.
If you're a backpacker you'll be competing with boat people for jobs... minimum wage is $550/w but 10% just disappears in to a "Super" rip off, and the rest will vanish in taxes and medicare surcharges.
That sums it up, bring as much money as you can or you might not last a year

.
Also because there are a lot of Great Whites, savage sea lions, Stingers, Tiger Sharks, Bull Sharks, most venomous Snakes/Spiders/Ants/Roaches/Bees/Flies/Fleas/Trees/Fish/Octopy/Dogs/Devils/Wombats/Birds in the WORLD and Medicare will only help you if you're about to die and then charge you for the ambulance... get medical insurance.
If you can afford A$7000 a month you can rent a nice place on the beach and have Tiger prawn BBQ everyday, with friendliest people... and life will be super sweet.