If you want to learn about marketing -- or any subject for that matter -- you can't go past a good book.
Of course you can buy them at some of the major Australian stores -- either in their shops or via their websites. But they often have inflated prices.
That's why you should check out Book Depository. This is a huge international site with millions of titles at bargain prices. They don't take too long to get to you either. Best of all, they offer free delivery.
And if you're a student looking for cheap textbooks, then you should check out The Co-Op.
Given how competitive the prices are on these sites, you'll often be able to buy one or two more books than you would have if you purchased them offline.