If you use contracts for phones, alternatively described as using pay monthly plans,
it means you can get the latest handset and spread the cost over the total
length of the contract. This is in addition to your monthly allowance of minutes,
texts and data to use the way you want.
A SIM Only plan means you'll
only get a SIM which allows you to use a certain number of minutes, texts and data
each month. A SIM plan is cheaper than a phone contract but you'll need to already
own a phone or buy one separately before you can use it.