Australia may be the smallest of continents but it sure has just about feature or landscape as all the other continents. Just within this small continent, you can find a variety in climates and attractions. You can rough it or you can bask in luxury. You can experience rural settings or go totally urban. Whatever you are into, Australia will probably have it.
Once you get there, hotels in Sydney and most of the major cities are available for reasonable prices. While Sydney, I think is a must when visiting Australia, if you have time, also visit cities like Melbourne and Brisbane. Hotels in Melbourne as well as hotels in Brisbane are plentiful and can be downright cheap.