Be aware this is converted from SGD so it may be a lower discount if youre buying from aud. Last time I used this service in 2013 $20 = $21 sgd = 20,000CC.
By current currency conversion $20aud = about 18sgd… Purchase with caution. Or just go into a physical outlet like ebgames, 711 and buy a cherrycredits scratch card.

Copied and pasted from the website.
This weekend just got better! From 08 Mar 2019, 0000HRS (GMT+8) to 10 Mar 2019 (GMT+8), you can now snag Steam Wallet Codes (all regions) at 20% discount! The clock is ticking so grab this deal while you still can:…

Terms and Conditions
• Each Flash Sale will start at 0000HRS of the stated start date and end at 2359HRS of the stated end date.
• All timings stated are in the GMT+8 time zone.
• Unsuccessful transactions do not qualify for the bonus / rebate / discount.
• Any disputes will not be entertained 1 month after the transaction date.
• All decisions made by Cherry Credits are final.
• Terms and conditions are subjected to change without prior notice

All Codes bought from Cherry Credits are enabled only in the following countries:
Australia, Bahrain, Brunei, Cambodia, East Timor, Hong Kong, Indonesia, India, Kuwait, Laos, Malaysia, Myanmar, Oman, Philippines, Qatar, Saudi Arabia, Singapore, Thailand, Turkey, United Arab Emirates (UAE), Vietnam, Korea, Nepal, Taiwan, China, Pakistan, Macau.