Hello Jacob and welcome to MR.
Well, we Aussies are disadvantaged but there are heaps of resources for books. One of them right here on MR : the
book upload section for classic, formatted by MR members.
Check out the
Freebie & Deals - you might find something. So far I have not been able to buy from Sony, but at least I can get the freebies.
Inkmesh is a good source to find books & compare prices.
I buy a lot on
Smashwords - good prices and lots of unknown authors. I love it there.
Check out this
thread from desertgrandma - good tips there.
I also buy books from booksonboard (US&UK) but have to use a US / UK adress (I live in a football stadium

).
Don't worry - there are heaps of resources for us to get books from - it's just a bit of a hassle to start of with. Oh, and check out your library, the one in Brisbane has an ever growing collection of eBooks.