The Coles catalogue says that the $50 Starter Kits are on special for $20 starting 30/05/18 according to this link and the catalogue link
I have rang up Vodafone and they have told me that when someone activates a $50 Starter Kit they have a number of options
There are Prepaid Mobile Phone options
Data Combo (35 days)
Talk Combo (35 days)
Prepaid 365 Plus (365 days)
And there is a Prepaid Mobile Broadband option
Prepaid Mobile Broadband
35GB data (10GB+25GB bonus)
Bonus data (25GB) may take up to 72 hrs to appear.
Must be activated by 14/08/18
The Vodafone Helpdesk that said that the Starter Kit may be activated on any of the plans and in the comments below some people have commented that yes customers have a choice of options when activating.
Personally I would make sure that the Starter Kit says "Vodafone Prepaid $50 Starter Kit" (as illustrated in the catalogue)and not Vodafone Prepaid Cap Starter Kit. There may be a difference.
Anyone with more information is more than welcome to comment below