Audible is AUD $16.45/month which includes 1 credit a month and access to the Plus Catalogue.

As an Audible member, your subscription includes: 1 credit a month* to buy any title you like, regardless of price—yours to keep, even if you cancel. Access to the Plus Catalogue—a selection of thousands of Audible Originals, audiobooks and podcasts, including exclusive series. Exclusive member-only deals. *Other membership plans also available

You can cancel your membership at anytime at no cost. Titles added to your Library with a credit are yours to keep, even if you cancel.