I bought amaysim plan a couple of months ago.
Received a promotional email two weeks ago but ignored because I thought it's $10 each renewal.
Received another email reminder today and found it's a one-time $10 for the next 8 renewals.
Seems to be a good deal.
Not sure if it's targeted or only for existing customers.
It said offer ends 20 Feb so today is the last day.
The URL in my email seems to be a unique link only working for me.
No idea if there's a universal URL for the deal. I would recommend checking your emails(or junk emails folder).
The deal link has two pics as proof.
According to raylud, this deal was confirmed by amaysim.
According to shanesimmo, the expiry date may vary.
According to jacknomiz2,
"It is an exclusive offer for selected customers specifically for the ones who bought the sim from Groupon."