That's if there is any competition and as we know there isn't any for Australia Post with small stuff.
Mind you for anything larger that you would use a box for there are many options now available.
I use the following online service which give you plenty of options, 
www.interparcel.com.auMost items that will cost around $30 via AP can be sent substantially cheaper via Couriers Please through Interparcel for around $12.00 and that's a door to door service as well but only from metropolitan area to metropolitan. Regional is a totally different kettle of fish where AP is mostly a cheaper option I've found.
Check it out for yourself.
Cheers,
BB.