TalkTalk is offering free smartphones to custumers who join its new mobile service.

However, users have to lock themselves into a two-year contract, and the offer is only available to those who have been with TalkTalk home phone or broadband for at least three months.

TalkTalk, which for years only sold other providers' mobile deals, is using the Vodafone network for its service.

While the phones themselves are free, the better the handset, the higher the monthly charge.

The cheapest, most basic package, aimed at 'light' users, costs £5 a month and includes a free Samsung Galaxy Y handset.

iPhones are not available, but there are another four handsets to choose from, including the mega-popular Samsung Galaxy S III. This costs £25 per month on the minimum package.

There are three plans available:

  • Small: 100 minutes, 250 texts and 100Mb of data, starting at £5, dependent on the phone.
  • Medium: 300 minutes, 3,000 texts, 500Mb of data, starting at £10, dependent on the phone.
  • Large: 1,000 minutes, 3,000 texts, 2Gb, starting at £20, dependent on the phone.

Those who sign up online will get double the data allowance at no extra cost.

But "out of bundle" costs are high, with calls costing 30p a minute and data charged at 5p per Mb.

Sim-only

TalkTalk also offers Sim-only deals, where there are no tie-ins.

For £10 a month, you can get 200 minutes, 3,000 texts and 100Mb of data. However, rival operator Giffgaff offers 250 minutes and unlimited data and texts for the same cost.

Ernest Doku, telecoms expert at price comparison site uSwitch.com, says: "Transparent pricing and double the amount of data for anyone that purchases their contract online will get the thumbs up from mobile customers, but there is a catch: no flexibility on contract length. It's 24 months or nothing."