Do all phone deals include a free SIM card?
Your Subscriber Identity Module, otherwise known as your 'SIM', is used to identify you as the carrier of your phone. Everyone have their own SIM card, and this will carry their phone number, data plan, and other details within it. It can be treated as a digital identity card. As such, when you purchase a new package or a new phone, you can continue to use your same SIM card and data plan.
Neat, functional and fashionable; the BlackBerry Z10 Smartphone
On older phone models, your SIM card carried your contacts and text messages as well. Nowadays, however, modern smartphones will carry these details on the actual device itself. The specific purpose of the SIM, therefore, is purely to link you to your data plan and phone number. When you use your specific SIM in different phones, you will still be able to access your pre-paid plan, or phone contract, without any trouble.
However, you need to be aware that SIM cards come in different sizes. Different SIMs will fit into different types of phones and card modules. So, for example, if you have a BlackBerry, and you lose it, you will need to get a new SIM card if you start using a different type of phone as a replacement. This SIM will be 'programmed' to still carry your data, but will be specific to the type of phone it is used in.