Just found this deal on ebay US. I've tried purchasing something and can testify that it works. You will need a US ebay account for this to work.
I've tried this on gift cards and it does not work. Can only be used once per account.
You need to find something that is over US$5. I found a usb c cable from an Australian seller for US$5.01 (A$6.94). I added it to the cart, applied the coupon code and paid US$0.01 for the cable.
The same cable is selling for $4.49 through ebay Australia.
Another good deal is the Xiaomi Mijia 0.5mm Metal Sign Pen - GOLDEN for $0.06. This is selling for $6.99 through ebay Oz (thanks doweyy).
Oh, for the 1c cost, I didn't bother about cashback. But if you're really keen, there is 1% cashback through Cashrewards.
Instructions (thanks Blue Cat)
Open Private Browsing Window
Go to ebay.com (not .com.au)
Register using fake United States address
If asked for phone number, press "Remind Later"
Add pen to cart
Press checkout
Now you will be forced to add a phone number, just change your number format from US to AU
Confirm with AU number
Apply coupon
???
PROFIT!
How does one filter by Australian sellers on the ebay US website?
Is there a way to see items whose locations are in Australia?
Also can't seem to see the other items listed by the seller of the Xiaomi pen (gearbite), think there are some bargains to be had there.