My country is probably different to yours. But I just visited their store. You can order them online from their stores too.
PAYG is a little confusing these days because every network provider is advertising it as if it's a pre-paid monthly plan. Ie. Top up $10 every month to get x bundle. But they're just the same as back in the day; they just massively emphasize the deals you can get when you top up every month because they want as much money as possible.
If you read their terms and conditions, they state that the regular price for a text, a call, a MB of data is y when you haven't qualified for a bundle. Don't get me wrong, the out of bundle prices are shockingly expensive but if like me, you want it to mainly receive and very rarely send it's not that bad at all.
I use my PAYG SIM as a secondary SIM. It would be too expensive to use as my main SIM. For the same allowance, the best PAYG bundle I could find was twice the price as my regular monthly contract.