Three free audio books (The Family Law, my Brilliant Career,The Rosie Project) when you purchase will do a $0 charge to your associated credit cards. No choice in the books. This may only be for people already members, not sure, but you may have to see if you join and see if you can get it.
From the site:
The Family Law: Meet the eccentric and endearing Law family. Your guide to life in the Law clan is Benjamin, the third of five children. Hilarious and moving, The Family Law is a linked series of tales about growing up the Law way from this wonderful Australian talent.
My Brilliant Career:This thinly veiled autobiographical tale tells the story Sybylla Melvin, a headstrong, talented girl struggling against the confines of life in rural Australia at the close of the 19th century. Franklin's story is a fun romp and a deeply moving journey, but above all it is a coming-of-age masterpiece.
The Rosie Project: Meet Don Tillman, a socially inept professor of genetics, who’s decided it’s time he found a wife and so begins The Wife Project. But Don is yet to learn that despite the best scientific efforts, you don’t find love, it finds you. An hilarious and heartwarming tale.
It appears that it has switched me to an Australian account when I did this (and I have lost my existing credits).
I have emailed audible for help.
EDIT
just checked in at audible.com, and still have existing credits - just don't have any at audible.com.au DOH!