There are all different stores around, some have specials at the right times too. Just luck of the draw sometimes. That link will help most of the times. http://www.pandacomputer.com
A mate recomends this store in Vic. also.
Go down the local Newsagency and pick up the Computer Market Mag.
for plenty of other traders around.
My mum just got some stuff from MSY Queensland and had no problems.http://www.ozpriceguide.com/
Here is another link for a price finder in Aus.