Become a member of a large holiday park chain and receive discounts on accommodation. Very handy for long term travellers.
Buying ice for your esky will be cheaper if purchased from the supermarket instead of a petrol station.
Choice research found Queensland to be the cheapest state for groceries.
Stock up on groceries in larger cities and towns as you pass through as they usually offer cheaper prices. Stockpile everyday items like tea, coffee etc so you don't feel compelled to buy essentials from roadhouse in the middle of nowhere.
Shop wisely and buy plain, boneless beef in bulk from the butcher and ask them to cryovac (vacuum seal) the meat. This will help with storage and extend the shelf life, particularly handy if you are heading to remote areas.