Dath, it best to check the website of the Customs or Revenue Service in your country. No doubt there's a page explaining every single detail about how much, when, and how to pay import duties. You''l usually will just receive a notice that your package has arrived in Australia, is currently on hold with the Customs Service, and if you want it you'll have to make a bank payment to such-and-such account. If you don't want to pay or think they're charging you too much, you can complain by filling out a form. Remember that in principle EVERY imported item is taxed to a certain degree; some with 0 percent (yes, zero %), others with more. There are lists specifying how muc import duty goes on which item. But for the finer details check your Customs or Revenue Service's website.