I saw this from a Facebook ad. This seems to be a continuation of https://www.ozbargain.com.au/node/571497. I would comment there but the post is expired and comments closed.
The page says "Sign up by 31/12/2020 and activate the SIM by 31/01/2021" but the "buy now" button still seems to work, so I'm not sure if it has expired.
Seems cheap - what's the catch? Paying $39/month for similar plan from Optus (although I think it has 10gb data)