Books in Australia are really expensive. This is because Australian publishers have managed to extract their own big cut from Australian consumers. Part of this is because they publish memoirs from any politician and partly because the printing industry is concentrated in some swinging electorates.
https://www.abc.net.au/triplej/programs/hack/cheaper-books-b...
What Australians often do instead is get ebooks through other means. Libraries are also more attractive for cost reasons.