How to find the best Sim only deal for my iPhone? Lot's of people already love the iphone they have, it is good enough, fast enough and modern enough to run the latest iOS operating system - so why upgrade iPhones? Often this question is answered by not upgrading to a new iphone but by changing to a better sim only deal. Often one can save a lot of monthly outgoing cost by choosing a sim only plan and keeping an old iPhone. Read our guide to choosing the best sim only deals!