Chuck in my 2c
I had a very cheap domain registrar in Australia (was $15 or there
abouts for a couple years i think)
They ended up going under and screwing me over rather well. After a
lot of trouble i ended up getting the domain again off the provider
they sold all their domains too and i've had way better service with
them. (boy that was painful though to start)
I think cheapest prices are down to sub $10US if you look on the web
(not .au of course as they are way dearer)
So couple things to note.
Do you need a .au? if that's what you are after
Can you afford to lose that domain name if it all goes really wrong?
And i think what you are paying for is the quality of service. A good
server where you can change domain details readily is critical.
Automated systems work fine for me.
WEZ!
probably go with recommendations i think as a best starting point