iPhone 6

Apple has just launched two new iPhones in the form of the iPhone 6 and iPhone 6 Plus. You're probably tempted to buy one of them but before you do, here's why you shouldn't do it on a contract. See also: The best smartphone you can buy in 2014.

There was a time when phone contracts were good value for money but by and large, those days are over. Now, the providers of said agreements require you to sign up for typically two years by which time you're shiny smartphone is at least two generations behind the times.

Deep down, you know that you don't want to be locked into a phone contract for 24 months of your life and there's good news: you really don't have to and not selling your soul to the mobile phone networks will actually save you loads of money. Read: Where to buy iPhone 6 and iPhone 6 Plus in the UK: Price, pre-orders, deals and contracts.

The iPhone 6 is a prime example of why you should go SIM-only rather than buying a smartphone on a contract and we've shown our working below.

iPhone 6 on a contract

We've done some extensive looking around at the best deals and over at Three, you can get a 16GB iPhone 6 for less than £40 per month if you pay an upfront cost for the handset itself. This deal gets you unlimited texts and minutes plus 1 GB of monthly data allowance.

That might sound pretty good for a brand new smartphone but when you add it all up, the total you'll spend over two years is over a grand.

Upfront phone cost: £99

Monthly fee: £38

Total: £1,011

iPhone 6 with SIM-only

While that contract might seem like a good deal to you check out this method of doing things. If you go straight to Apple and buy the 16GB iPhone 6 it will cost you just under £550 and it will be the same model which Three (or any network) will give you on a cheap tariff.

Once you've got the phone, you need a SIM to go with it and GiffGaff will give you one for a rolling monthly cost of £10 giving you a similar amount of stuff: 1 GB of data, unlimited text messages and 500 UK minutes.

Add it all up, and over two years you've saved a tasty £232. You can change your SIM deal at the end of ay month and when a new smartphone comes along you can sell your current device and use the money towards an upgrade. This way you can always have the latest smartphone on the best tariff for you.

Phone price: £539

SIM cost monthly: £10

Total: £779

Before you comment

That's just one example so isn't a one-size-fits-all guide, it will work for some smartphones and not others depending on what deals are around and your requirements. Even on more expensive tariffs from GiffGaff, the SIM-only option is still cheaper so you may save money and get more data allowance (including 4G). We're highlighting GiffGaff as a good source for a SIM-only in the above example but there are many places, including the networks, where you can find a good deal.

It also, of course, requires you to be able to afford the large outlay on the smartphone in the first place which may not be possible for some.

The point is that you should always investigate getting your smartphone outright with a SIM-only deal before you sign on the dotted line. There's a good chance you'll be better off going it alone.