A postpaid plan is a subscription: you pay a recurring monthly amount and the provider bills the difference. A prepaid plan is a purchase: you buy a block of credit with a stated expiry and spend it down.
What that changes for you
- There is no bill at the end of the month, so there is no surprise charge to argue about.
- The term is set by the provider, not by the calendar, which is why 28 day and 186 day products exist.
- Unused credit does not carry by default; rollover has to be earned by recharging before expiry.
Why the amounts look odd
Look at a real table and the pattern is clear. The Boost prepaid table prices by recharge amount, and the Optus data only table runs $20, $30, $60, $80, $90, $130. These are product choices, not mistakes: the provider is choosing which behaviours to reward.
The practical consequence is that comparing two prepaid plans means comparing the cost of the data you will actually use over a whole year, not the headline number.
What we could not verify. Where a provider has not published a figure we mark it unknown rather than estimate it. Re-read the provider page linked below on the day you decide.