Schooling (Kuala Lumpur)

Hi, does anyone know why international schools are so expensive? My kids go to a private school here in Australia, but nothing like schools there. Seriously more than 100,000 Australian dollars to send 4 of my 5 kids. Shouldn't it be cheaper? Has anyone experienced any private or other school that is cheaper and still good for primary and secondary? Can our kids go to other schools that aren't international ones? What dies everyone else do? Any advise appreciated. Thanks.