Just looked at Vodafone for sim-only deals, are these iPhone only tariffs new?
£20/m will give you either:
600 mins, unlimited texts, 1GB data (12 months)
or
900 mins, unlimited texts, 500MB data (12 months)
or
600 mins, unlimited texts, 500MB data (30 days)
That and also Quidco giving £100 cashback on the 12 month tariffs, seems like a much better deal getting one of these and paying full price for the phone.
i think they're being updated to those you mention, as clicking on the 30 day one, gives you a page error.