Does the Australian Air Force Cadets cost any money?

No it doesnt, Australian Air Force Cadets is completely free .

In fact if you are considering joining I can give you all of the information you might need. I have been a part of the AAFC for two years now so if you want to join email me at hugo.cordukes-lane@tsc.nsw.edu.au

I hope this answers you intended question

In some SQN's it does cost money

For example in 6 Wing it cost $170 for your first year and $150 for every year after that