Sydney's living expenses will definitely be higher than in Perth.

I'm in Melbourne, and I am going to assume Sydney will be similar to Melbourne.

I don't know how well off your family is, but I used to spend about AU$800-a-month.

That was because I used to live by myself, and I didn't think it was worth cooking for one person.

This year I will be living with my brother, so its more worth it to cook for two people. I guess I will be saving money by not eating out all the time.

Accommodation can vary depending on your standards, but generally I'd say about AU$250/AU$300-a-week (excluding bills) for property if you plan to live in the city, and it will get cheaper if you plan to live further away from the city.

Once again, if you have a housemate, living weekly expenses for food, etc will be cheaper. I recommend you get a housemate, as you can split groceries, utility bills, etc.

Not so sure about Sydney's public transport system, the last I went there was like 10 years ago I think, so I can't really remember.

Take it into account this is based in Melbourne, but as I said, I expect Sydney to be quite similar.

And I am not sure what it's like in Perth at all, as like Sydney, I went to Perth also 10 years ago or so.

Oh, if you have some free time, a part-time job will be very useful, financially and also for your CV.

Working in Australia is not like working in Malaysia, the pay is actually pretty good, even for students working in McDonalds (who generally don't need to support themselves), there is a minimum wage.

Well, since you have friends going, if you do pick Perth with them, then do consider living together. It will save you a lot of money.

As thugs said, meals generally cost about AU$10. If you cook with friends, it can come as cheap as AU$4-AU$5 (more or less) per-person (depends on the number of people, obviously).

I heard in other states students get concession prices for public transport, even international students.

In Melbourne, international students don't get concession, unfortunately.