I am on the Gold Coast, at the southern end of Queensland.
Cairns is a tourist destination and the prices reflect that, unfortunately. Make sure you get out to the Atherton Tableland and do the Kurunda trip.
If you consider the prices in Cairns are high, wait until you get to Alice Springs and Ayres Rock.
In Sydney and Melbourne the prices should be a little cheaper. Do all the tourist things but try to eat where the locals eat.
Hope you enjoy your stay, there's a lot to see but it is expensive.