Expenses
Australia is a pricey destination. Food, travel, and lodging costs should not exceed $100 each day. Transportation in Australia is expensive, so if you want to take a road trip around the country, buy a new or used automobile online. There are several websites in Australia that offer much cheaper rides around the country.
Try hostels for lodging; they are inexpensive and not as filthy as you may assume. If you're traveling with your family, a private room will still be less expensive than a hotel room. If you're looking for an adventure, go camping.
Cooking your own meals is much less expensive than eating out. Eating out every meal would be detrimental to your budget.