The Prepaid Daily Maximiser is a daily usage plan, it doesn't allow for individual data top-ups.
$2.00 a day for 1GB of data (You'll get an extra 512MB data to a maximum of $4/1.5GB for the day).
You'd be better off on our Prepaid EPIC data plan. There's heaps more data to use and the option of adding data packs.
I'm following up on the 999 menu issue.
Just waiting on a response back from one of the platform managers.