Captain Fathom has reminded me that actually I did buy an ERSA with RDS, and borrowed an AIP. You can't sit the exam without knowing those quite well. You shouldn't need anywhere near the maximum number of tags permitted.
As far as CAOs and the like, yes, they are very expensive to buy and maintain just to pass the exam as a one-off. Now that I'm actually working in Australia I maintain (& regularly review) a current set of all required documents. But not CAOs - that's what the interweb thingy is for.