Australia can be expensive I have to agree with you but I also think is worth the money to see such beautiful and sophisticated cities, to see so much beauty (at least once).
A travel package is not always the cheapest way to to go, you can check this link
Flights to Australia you might find what you are looking for.
Also you can take a look at
Sydney Hostels and
Sydney Hotels and you have
Melbourne Hotels, this one I think is very atractive
Perth Hotels.
Another Perth accommodation offering plenty of comfort is the Sandringham Hotel Perth, also known as Sandringham Village.
The Sandringham is a resort village, located about ten minutes from the heart of Perth. One of the aims of the Sandringham Hotel Perth is to offer a less expensive alternative to some other Perth hotels.
Australia Tours might be useful to you also.
Have a great time!