You should download Wikicamps (about $8 to 10) and a decent Fuel app (I use Fuel Map). Travelling in Central Oz is not much different to anywhere else. Prices vary between towns, CP prices tend to be less seasonal than coastal areas but can be dearer in touristy spots and times, fuel and food prices can be over the top when you have little choice.
A very warm welcome to the forum Tony you have another Wiki supporter here I have tried a number of other options but you cant go past reccomendations from fellow travellers
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Hope that it is not too late for me to say, welcome to the forum Tony
I really do like the sound of that name
Apart from the good advice from everyone above I have been on that road and stayed in free camps only, therefore I know nothing of the caravan parks in that area
I did find a lack of toilets, and drinking water, so it may be advisable to have a porta pottie, and carry extra water, if you are not self contained, and wish to free camp
I purchased water in Coober Pedy, which is a well thought out system, you put your coins in and use something similar as a fuel bowser nozzle
Other places where I enquired about water, it was bore water
thanks for your information, it is helpful. We are self contained, but need to know were water stops are. We still in the finders ranges leaving for Port Augusta next coming Thursday to do washing and shopping, before leaving to Roxby downs.
I really do like the sound of that name 
