It didn't take long for the Kickstarter-funded Cards Against Humanity to become the defacto party game, eclipsing traditional favourites Charades, Pictionary and "Guess the Toe". The problem for Australians however was two-fold -- the original game is full of American references, which are often unplayable and the pricey hoops you have to jump through to acquire a copy (unless you're happy to print it out). Both problems have evaporated with the release of the Aussie edition, which you can buy directly from the CAH store for a very reasonable sum.
If you hit up the Cards Against Humanity website, you can now select "Australia" as a region, after which you'll be directed to the product page for the local version. $30 is all you need to get it and best of all, the price includes shipping.
You can grab the game's five expansions as well, but these are not localised, so be prepared to shift through these and pluck out the US references. Alternatively, just stick with the base game -- $30 is a steal compared to your options locally, where you'll have to contend with a lack of stock and a price tag of $50 or more.