If you don't like to be locked into a long contract, and can afford to buy one outright, then buying your iPhone SIM-free and choosing a SIM-only deal may be best for you. Not only are you able to upgrade your iPhone when you want to but you can make use of cheaper contracts too.
We take a look at our favourite SIM-only deals for iPhone from the UK's top networks.
EE are the only network to offer double-speed 4G making them one of the fastest networks and the perfect partner for your iPhone 6s. All of EE's 4G plans come with inclusive tethering and big data allowances or if you go double-speed 4G you'll also benefit from inclusive EE roaming.
EE is a visual voicemail enabled network so you can make the most of your iPhone's features. EE also supports WiFi Calling, so you can use your WiFi connection to make calls if you're in a poor mobile coverage area.
Our favourite EE SIM-only deal
Vodafone is one of the longest running mobile networks in the UK and the world's second largest operator. As a customer you can expect wide mobile coverage, inclusive calls to UK numbers when you travel within Europe, 4G as standard and 3 months of unlimited data while you test-drive the network and decide how much you really need.
And, if you choose a Red Value plan you'll also be able to add up to 12 months of Netflix, Spotify, Now TV or Sky Sports Premium to your plan at no extra cost.
Our favourite Vodafone SIM-only deal
O2 is a Visual Voicemail enabled network so you'll be able to make the most of your iPhone's features. O2 operate an established 4G network so you'll experience excellent coverage across most of the UK. But, if you happen to live in one of those mobile signal not-spots than O2's Tu Go app lets you make call, send texts and check your voicemail over you WiFi signal instead.
As an O2 customer you'll also have access to 1000's WiFi hotspots nationwide and O2 Priority Moments where you can claim lunch for £1 every Monday and get access to gig tickets up to 48 hours before general release.
Our favourite O2 SIM-only deal
Giffgaff is a no contract, online only mobile network that do things a bit differently. You won't find them on the high street, instead giffgaff keep their costs low by doing away with expensive shops and call centres. As a customer you can expect great coverage - giffgaff use O2's network, low cost flexible plans (or Goodybags) with no ongoing contract, free calls to other giffgaff numbers and, in case you do need any help, a loyal and helpful online community to answer any of your questions.
Giffgaff also offer flexible payment plans if you want to buy your iPhone outright and SIM-free.
Our favourite giffgaff SIM-only deal
Tesco Mobile is one of the largest Mobile Virtual Network Operators and uses O2's 3G and 4G network. As a Tesco Mobile customer you can expect low cost 4G plans, have complete control of your spend with capped contracts and of course it wouldn't be Tesco without Clubcard points for every pound you spend.
Our favourite Tesco Mobile deal