As SWIMBO has said below if you are here on a PR visa then the fees would be commonwealth supported just as an Australian Citizen is, but unlike them you are not entitled to get a student loan to cover those costs (known as HECS). Your fees would need to be paid up front before each semester.
In terms of entry requirements, each University have different requirements. They also may give you a different score for your A levels (not too different). A good rule for would be that students must have a minimum of six points for entry to university and have completed at least three ‘A’ Level academic subjects.
The scoring system guide (need to confirm with each University) would be
A*= 6, A=5, B=4, C=3, D=2, E=1
Again just to give you an idea of entry for a business program at the 3 Universities:
UniSA - Bachelor of Business – Score of 7
Adelaide Uni - Bachelor of Commerce – Score of 9
Flinders Uni - Bachelor of Business – I can’t see their score published but you can contact them for this
I won’t comment on which is best as I know both Adelaide and UniSA are good due to their international ranking. Flinders may be equally as good it’s just that I am not as familiar with their business program.
My advice would be to try not to treat the entry requirement as measure of quality but more a supply/demand. We have programs in my bit of UniSA that has an ATAR of 99+ but that is not because it’s any better or necessarily more difficult than the same program elsewhere or another program at UniSA with an ATAR of 60 or 70, just there is a huge demand for the program and limited places so it is high to ensure we get the best of the applicants. Business (coming from someone who studied business himself), can afford to offer more places than other programs and with all 3 Universities offering it we can all afford to have a lower ATAR than say medicine, physio or law. Does not make business a lesser course or less difficult.
If you want more info about the UniSA business courses I have a great contact if you PM me.