A:Answer First, there are two versions of every single IPad, a Wifi only version and a cellular service compatible version. The wifi only version is always cheaper but you can never add a data plan to it. A cellular service compatible version can be bought unlocked (which is usually more expensive, but you can pick your carrier and change carriers whenever you want), or tied to a cell phone carrier like At&T, Verizon, or Sprint, who will usually then give you a discount on the device, still not as cheap at the wifi only version but cheaper than unlocked