By Martin Lewis, April 28, 2010
Millions of people bought iPhones from o2 when it launched a few years ago, and many of those phones are now out of contract.
Yet you could still be paying a hefty £30-£45 per month tariff. But there is a simple way to slash this.
Sign up to another year's contract, still with o2, and for £15 a month you get 300 any time, any network minutes plus unlimited texts and data - the same you would pay £35 per month for if you simply carried on with an old contract.