Prices are going up. £20+ for my unlimited SIM deal. Three haven't offered anything worthwhile. They offered 70 days taster of roaming when signing a new deal.

£15 until April then £17.30 then £19.60 24 months.
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I just tried 333 they said they would match £15 but with rises of £2.30 in April and to counter the rise it's a 12 month contract.
I should have switched to iD but I can't be arsed. Three have been alright too. £17.30 unlimited everything.