https://elevate.mastercard.com/benefit/product/166859/amazon-aus-generic?ac=amazon-australia

New-to Amazon Prime customers will enjoy 3 months (90 day) membership. Existing Amazon Prime customers will receive a AUD15 Amazon gift card directly into your Amazon wallet. 

Says that it's for 'World and World Elite MasterCard Cardholders' but others over at OzBargain have had luck with a Westpac low rate credit card etc. YMMV. 

If you're successful: 

Prime benefits

Entertainment benefits include:

• Prime Video gives you unlimited access to Prime video content. Find out more about Prime Video.
  

   

  • Amazon Music Prime, which gives you access to two million songs, thousands of stations and top playlists . Find out more about Amazon Music Prime
  • Prime Gaming – Prime members enjoy a selection of free games every month, access to free in-game loot for some of the world’s biggest games, a Prime Gaming channel subscription every month, an expanded set of chat emotes and colours, an exclusive chat badge and more. Find out more about Prime Gaming.
  • Prime Reading – Members enjoy free access to a selection of more than 1,000 e-books, short reads, comics, travel guides, children’s books and more at any given time. With Amazon’s free Kindle reading app, members can read on any device. Members can start reading now by downloading the free Kindle reading app for mobile phones and tablets or by using any Kindle e-reader and Fire Tablet. Find out more about Amazon Prime Reading.

Shopping benefits include:

• Prime Exclusive Deals: Members get exclusive access to a selection of Prime member only shopping deals on Amazon AU.
• Prime Early Access: Get 30-minutes early access to Prime eligible Lightning Deals on Amazon AU. Find out more about Prime Early Access.
• Alexa voice shopping: Order or reorder Prime eligible local items by voice from your Alexa device.

Games to claim : Dragon Age Inquisition for Origin, Control: Ultimate Edition for GOG, and Need for Speed: Hot Pursuit Remastered will be free December 1.