Unlocked iPhone 4S Available, Costs $649 and Up
Apple has announced that unlocked iPhone 4S models will be available starting in November, slightly later than the general 4S availability for both the US and other countries. These phones will work on any GSM carrier worldwide, you simply need to pop in a local GSM providers micro-SIM card and follow the onscreen activation instructions. The dependence on SIM cards does mean that the unlocked iPhone 4S will not work on CDMA carriers, however.
Unlocked iPhones are ideal for users who travel internationally on a regular basis and need to be able to utilize local carriers, this offers a significantly cheaper option than paying the roaming overage charges through a home carrier like AT&T. Unlocked phones also provide a pre-paid option, allowing you to use GoPhone, T-Mobile, or other pre-paid GSM choices.
The downside to an unlocked device is the costs. The price of the iPhone 4S contract-free is quite a bit higher than the subsidized price through a carrier, with the 16GB model starting at $649, the 32GB model costing $749, and the 64GB model coming in at $849.