Contract Phones - you pay monthly line rental and you are billed for your calls. The call charges typically are cheaper and most contracts include some free minutes each month. Pay As You Go - If you want the freedom of wireless without the contracts, call plans, and monthly bills, then Pay As You Go wireless. The biggest advantage of this is that it is impossible to run up a huge phone bill SIM Free Mobiles - are brand new, unlocked SIM Free mobile phones that are sold without a SIM or contract. This means that you can put any GSM UK SIM in them whether on pay as you go or an existing pay monthly contract. | 
