Just noticed a banner when I browsed amazon.
I got 2 credits and voucher instantly.
If you are not with Audible for some time, you can check if you are eligible of a free trial.
Also work if you are a Prime trial member, that's what I did.
T&Cs:
This promotion commences 7am AEDT March 30 2021 and expires 11:59pm AEsT April 28 2021. The promotion is valid for new members of Audible in Australia or New Zealand who sign up for an Audible 30-day trial membership at www.amazon.com.au. You'll automatically receive 2 membership credits for $0/month during the first 30 days of your membership (the 'trial period'). Second credit may be added at any time during first 2 days of trial period. After the trial period, membership renews automatically for 1 credit/month at the regular monthly price, currently $16.45/month. Cancel anytime. The offer has no cash alternative. Limit one per customer and account. The offer is non-transferable and may not be resold. Other terms and conditions apply, including Audible's Conditions of Use at https://www.audible.com.au/legal-terms/Conditions-of-Use?mod…. If you violate any of the terms or conditions, the promotion will be invalid, and the offer will not apply. This promotion may not be combined with other offers. If your credit card is declined, the offer will not apply. Terms prohibited by law shall be void without prejudice to the remaining terms.
I think 15$ audible voucher .. just anyone read as Amazon voucher