SIM only deals are the cheap iPhone X and iPhone 8 alternative

We probably say this every September, but it's difficult to remember greater anticipation for a new mobile than today's iPhone launch. Celebrating 10 years of the iPhone, it looks certain that Apple is going to drop not one, not two, but THREE shiny new iPhones.

We don't know their final names yet (iPhone 8, iPhone 8 Plus and iPhone X are the current front runners), but we are 100% sure that they're going to cost a small fortune to buy. Think we're over exaggerating in all the excitement? Well expect to see prices start from no less than £650, and we're predicting that the iPhone X to start at almost £900. Go on a contract, and we'll be shocked if you can get away with much less than £50 per month and £1,300 over the two-year deal for the X.

But getting a separate SIM card - either for your new iPhone or an old 6 or 6S - could save you a lot of cash. Three is the network that leads the way on cheap SIM only deals, but there are other offers worth considering, too. Keep reading to see how much money you could save if you grab a SIM card for an unlocked iPhone now.

Best Three SIM only deals

If you need anything more than a trifling amount of data for your phone, Three is consistently the best value SIM only network in the UK. While Vodafone and EE sometimes manage impressive special deals and tempting cashback offers, Three's tariffs are perennially brilliant value.

Here's the pick of our favourites:

To put that into context, the cheapest SIM only deal you can get directly from EE at the moment costs £15.99 - and that's only for 1GB of data. Vodafone's cheapest is £15 per month (again for 1GB) and although O2's £13 SIM gives a slightly more generous 2GB, it's still not a patch on Three's prices.

Can I get unlimited data?

Three is famously the major network that offers unlimited data - none of Vodafone, O2 or EE offer totally uncapped data to use every month. You can get it for £27 per month and you also get unlimited texts (although you're limited to 600 call minutes a month).

That said, if you have no qualms about getting your Three SIM from another retailer, Buymobiles offers unlimited data for a mere £22 per month. And to sweeten the deal, there's £35 cashback in it for you as well.

Are there cheaper SIM only deals?

There are indeed. Although Three beats the rest when you start looking at 4GB of data and more, it's the Carphone Warehouse brand iD that has the very cheapest SIM only deals.

If you're scarcely ever away from Wi-Fi and just need the cheapest SIM card out there for your mobile, then you'll want to check out this £3.99 per month tariff for 500MB of data. Pay an extra one pound and one penny and you can double the data to 1GB. You also get 500 minutes of call time and 5000 texts - that's really great value for just a fiver a month!

Any other SIM only special offers I should know about?

mobiles co uk

Phone retailer Mobiles.co.uk (another offshoot from Carphone Warehouse) has a very cunning - and tempting - trick up its sleeve to get you to obtain your new SIM from them. It's offering up to £99 cashback, depending on the tariff, to make the bottom line prices look very attractive indeed.

For example, its 8GB Vodafone SIM normally costs £17 per month, which can't really compete with Three's rates. But £99 cashback brings it down to an effective £8.75 per month. Need more data? Then its 20GB Vodafone SIM comes down from £20 to an effective £11.75 per month if you account for the £99 cashback.

There is a small snag though. To claim the cashback, you have to remember to submit a copy of your bill every two months to Mobiles either by post or online, and they will credit the cashback to you in five installments. So it's a bit of a faff, but the rewards are clearly great if you can be bothered.

New SIM card for iPhone 6S and 6

If you were one of the many people that bought an iPhone 6S contract deal when the phone first hit the shelves in 2015, you're contract will be coming to an end any time now. In fact, you've probably been pestered with dozens of calls urging you to upgrade already. The same goes if you bought a 6S Plus or bagged a bargain iPhone 6 or 5S instead.

But if you've managed to get through the two years without a cracked screen or scuffed camera lens and a fully functioning home button, then you'll probably feel reluctant to ditch it. Going SIM only for a year, or even a few months on a rolling 30-day contract, can make much better sense - at least until the Black Friday sales begin.

And if you're anxious that your old iPhone will be locked to your current network, don't be. Once you've finished paying for your two-year contract, the handset becomes unlocked, meaning you can put a SIM from any other network in there.

iPhone X and iPhone 8 on SIM only

We've spent a lot of time over the last few weeks predicting what kind of prices you should expect for the new suite of iPhones. And we're not talking about simply plucking numbers out of the air - we've looked at market trends and refreshed our memories about iPhone launches of yore to guesstimate figures that we're confident will be accurate when pre-ordering becomes available on Friday.

We reckon that the new iterative successor to the iPhone 7 - whether it be called the iPhone 7S or iPhone 8 - will be sold for around £650 as a standalone handset and no less than £1,100 on contract over two years.

While for the iPhone X (or iPhone 8 if that's what the 10th anniversary edition is eventually called) will probably be verging on £900 for the handset and £1,350 for a two year contract.

On that basis, shelling out a wodge up front for the handset and then signing up separately for a SIM only deal could make financial sense. If you go for Three's 4GB for £9 per month SIM for example, that would cost you £216 over two years. Combine that with our predicted handset prices, and you could save yourself a decent sum compared to what's on offer with a contract.