This is in the wrong thread but anyhoo...
Student Notes are also referred to as "readers" and are photocopied, bound books that are distributed by the University Copy Centre on the instruction of your lecturer, in direct relation with your course.
The main purpose is to provide you with a wider variety of sources for investigation, rather than the opinion of just one person in a textbook.
They are usually anywhere from $15 - $40 depending on the unit of study. They can be ordered online through MyUni/MyStudy. Some subjects may require you to get your readers from KopyStop on Mountain Street in Broadway.
Some subjects only have a reader, others have a reader and a textbook, others have no readers. It really depends on what your lecturer has decided upon.
Don't fret, you'll find out what you need in your first lectures.