Depends where you live.
With DS i went to an ultrasound place that was next to the Napean Hospital in Penrith. They charged $250 and you get alot back from medicare that way. You can get a dvd of the scan for an extra $5.

With this pregnancy i went to Sydney Pregancy & Ultrasound For Women in Windsor. They claim from medicare on behalf of you and only charged $70 on the day. I had 3 scans with them and they did 3D/4D every time for us. They also will give you a DVD of your scan for $10.