Andrew D replied:

Look up the fuel prices under the "resources" pull-down menu at the top of the page and average the similarly remote places and you will get close to what you could expect. Maybe ring the local police

bill replied:

Just a thought Steve but don't worry about the price - whatever they're charging is what you'll have to pay and it won't add heaps to your trip cost. I put 120l or so in when in Birdsville. At the time it was $1.15/l about 30c above Melbourne prices but when it's all boiled down it cost $36 more then it would have in the city. Availability is another story though - ring ahead if you can't find the info you want on this site. Remote areas run out from time to time eg Mt Dare had no diesel this time last year.