I am a student, and I notice that new writers can get very different paychecks for their first book. It seems to depend on whether they publish by themselves or go with a standard publisher. Things like royalties, how much the book costs, how many copies sell, and the contract terms all play a part. If you look up online book publishers in Australia, you might see different deals. Before you pick a path, it helps to read the terms closely and compare what is offered.