Australia's smallest legal tender is 5 cents. We had 1 and 2 cent coins, but they were dumped 10 years ago or so...
Also, $1 and $2 are coins, and all the other notes are plastic! That is the problem with US small bills - they are worn out so quickly that they have to be replaced really regularly. Plastic bank notes can easily survive the swimming pool or washing machine.
In terms of stores - if you pay by credit card / eftpos, you pay the exact amount of your purchases, but if you use cash, it is rounded (up or down) to the nearest 5 cents. You very quickly realise what a pain in the arse the small coins were. I say 'dump em'.
edit - I did a quick search as there was an old thread that actually had images of all the Oz notes, but, alas, I could not find it
