Whats the best and cheapers way to travel australia, should go alone or on a group excursion?

I think I would go alone and spend as much as I could. 20 years from now you won't remember what the trip cost you, you will just remember how much fun it was to travel that far. Will you really remember how much that room cost when you look back?

If you are traveling from NYC or London you could fly as a courier and save money on your flight.Go as a excursion with Contiki if you are 18yrs to 35.You will meet people from different countries and make new friends.

Do what all the other backpackers from around the world do in Australia - buy a Greyhound bus pass and stay in the huge network of youth hostels scattered around the country. It doesn't matter if you come alone as you will meet heaps of people to travel with along the way. If you only have a couple of weeks time however, something like a Contiki tour might be the best way to see some highlights.