From what I have seen about wireless at ANU, it will cost only the price of a wireless network card however will be limited by the same quota system used in the labs.
Walk up and plug in points are available in the library (also constrained by the quota system).
If you wanted to set up your own wireless network, you would need an Acess Point aprox $100 and a wireless card another $100 or so. Plug AP into college net, set everything up and away you go. Secure it though overwise a tech savy guy next door with a wireless card will start using your connection and you'll be paying for it.
Thanks for the help cheesgrater, it is a pity that it's that fast but that expensive, I suppose it reduced the urge to pirate. At least pre-paid makes it harder to run over ridiculously without realising. Do you pay for uploads or just downloads?