The Australian system seems a little different to the US. (all figures are quoted in Australian Dollars. Roughly AU$1.00 = US$0.90)
If you have private health insurance (optional system, you choose to have it if you want it, and pay a fee to have it - approx $60-$140 a month) it may or may not cover it depending on your plan. (alot of plans exclude expensive stuff like hip replacements, pregnancy, cardiac intensive care, laser eye surgery etc).
If you dont have private cover, it costs about $12,000 out of pocket.
My private insurance covered it - which means they pay the hospital bill and the cost of the band itself. You are then out of pocket for the Surgeons bill ($3000) and the anaesthetist ($1000)
Australia's free public health system - Medicare, gives you a small refund on your out of pocket expenses - about $400.
Consults with the surgeon cost $50, and Medicare gives you $35 back.
Fills cost $125, and Medicare gives you $108 back. (so very little out of pocket cost)
You can choose to have your surgery done as a public patient, and get Medicare to cover it entirely, but there is waiting lists, and you will wait about 4-5 years. (cannot choose your doctor or hospital)
You can also claim a tax rebate - if you have medical expenses of any sort over $1500 per year, you can claim anything above this and get 20 cents in the dollar back for every dollar over $1500. (you can include dentist bills, chemist bills, doctors bills optometrist, etc)