According to the ATO, if your studies relate to income earning activities, you may be able to claim a deduction for some of the expenses if you have met one of the following conditions when you incurred the expense:
the course maintained or improved a skill or specific knowledge required for your then current work activities
you could show that the course was leading to, or was likely to lead to, increased income from your then current work activities, or
other circumstances existed which established a direct connection between the course and your then current work activities
These deductions can include anything from textbooks, to internet usage to course fees and more!
Please note rules may change so please check with the ATO or tax agent on what you can claim as a self-education expense.