People signing up to Vodafone's £40 per month, 18-month contract also have to pay £89 for the iPhone itself, meaning they will have spent £809 on the phone and monthly payments by the time their contract expires.

O2 and Orange, which also offer the iPhone, are less expensive than Vodafone, though there's juyst 84p difference in price between the two: a 16GB iPhone 3GS on O2's £29.38 per month, 18-month contract will cost users £713.82 over the lifetime of their device, including the £184.98 initial outlay for the phone; the same handset on Orange's £29.36 per month, 18-month contract will cost £712.98 over its lifetime, including an upfront cost of £184.50 for the handset.

Telegraph notes that supermarket giant Tesco, which started selling the iPhone last week, represents the cheapest deal for shoppers, who can choose between a 12-month or two-year contract. The cheapest monthly tariff is just £20, but shoppers will have to pay a whopping £320 up front for the 16GB iPhone 3GS. The number of free minutes and texts available varies between networks and tariffs.