.... With one of the prepaid packages you get what you pay for, ie. unlimited data, 300 sms etc... These packages last 30 days (I think!).
You can Queue payments to roll the packages. But you can only queue two payments (I think!). If you're organised enough, you can always have a payment queued avoiding you dropping back to "unpackaged, payg" state.
I'm not on GiffGaff, but if I had to pay for my own phone, I would be.......... even if the thought of having to remember to top up would annoy me, the cost saving would make it worth while.
Also, it is an MVNO on O2.
IMO, O2 are the best in the UK.
/my terminology sucks.