Check if you are eligible for it here: https://www.amazon.com.au/prime
Terms and conditions for the $10 promo credit:
These terms and conditions apply whereby Prime members who spend $39 or more on one or more Prime eligible items in a single order on Amazon.com.au (“Qualifying Item(s)”) within 30 days of becoming a Prime member, will be eligible to receive a promotional credit of $10 for use towards a future Eligible Order (“Offer”). The Offer will only apply where the Qualifying Item(s) is shipped and sold by Amazon AU.
The Offer does not apply to purchases made from third-party sellers on Amazon.com.au (even if fulfilled by Amazon AU or Prime eligible), digital purchases such as e-books, subscriptions such as Prime Video and Audible, gift cards and postage or delivery rates.
The $10 promotional credit (for use towards a future Eligible Order) will be available to be claimed by the customer within 30 days after the Qualifying Item(s) has been ordered. The $10 promotional credit will be automatically applied to a future Eligible Order at checkout, only after the Qualifying Item(s) has been dispatched. The $10 promotional credit (for use towards a future Eligible Order) will expire upon 30 days of being claimed by the customer.
An “Eligible Order” refers to a purchase of $39 or more on one or more Prime eligible items, which is shipped and sold by Amazon AU and shipped at the same speed to a single address, in a single order on Amazon.com.au, and excludes products sold by third-party sellers on Amazon.com.au (even if fulfilled by Amazon AU), digital purchases such as e-books, subscriptions such as Prime video and audible, gift cards and postage or delivery rates. If you do not add the Qualifying Item(s) to your shopping cart, the Offer will not apply. If you cancel or return the Qualifying Item(s), you will only be refunded the price paid for the Qualifying Item(s), subject to the applicable refund policy, and the promotional credit will be invalidated. If you cancel or return the Eligible Order for which the promotional credit was used, you will only be refunded the price paid for the Eligible Order (that is, less the value of the promotional credit which will be allocated proportionally among all Prime eligible items included in your Eligible Order), subject to the applicable refund policy, and the promotional credit will be invalidated. This Offer cannot be used in conjunction with any other offer. This Offer cannot be used on pre-existing orders. This Offer does not apply to orders placed with 1-Click. This Offer can only be redeemed once per customer. The maximum benefit you may receive from this offer is one promotional credit of $10. This Offer may be withdrawn or amended without notice. This Offer is not redeemable for cash. This Offer is non-transferable and may not be resold. Amazon reserves the right to cancel the Offer at any time where Amazon suspects misuse, abuse or fraud. Amazon.com.au’s Conditions of Use and Sale apply. Delivery will be applied to each item in accordance with Amazon AU's standard delivery rates and policies.
nothing for me, so might be targeted