The iPhone redefined cell phones. Combining a cell phone with the iPod was impressive enough, but adding touch screen capabilities (in place of the "old-fashioned" slide out keyboard) and putting, quite literally, the world at your fingertips with thousands of "apps?" It was an ingenious invention marketed in typically brilliant Apple fashion, and before long everyone wanted the iPhone.

Except there was one problem: AT&T was the exclusive United States carrier of the iPhone, which meant everyone else was out of luck. The pool of potential users increased when Apple and Verizon agreed to a deal earlier this year that allows Verizon to offer the iPhone, but there are still a lot of people who want to buy an iPhone but can’t because their provider doesn’t carry it.

Or are there?

Unlocked iPhones—iPhones in which the AT&T or Verizon SIM card has been unlocked, i.e. disabled—became wildly popular on the black market almost from the moment the original iPhone was released in 2007. Some reports indicate that more than 25 percent of the original iPhones in the United States were actually unlocked iPhones and used by consumers who didn’t have AT&T as a carrier.

Now, AT&T—which originally required those buying the iPhone to sign a two-year contract with the provider—sells iPhones without the contract, though such cell phones are twice as expensive as iPhones attached to an AT&T deal and though the SIM card is still locked into the AT&T network.

Still, any opportunity to buy the iPhone legally without committing to a service agreement with AT&T or Verizon is better than no opportunity to do so. Of course, to some people, the idea of paying twice as much for one of the unlocked iPhones—instead of simply purchasing a phone carried by their provider—sounds like lunacy.

Why are people willing to go to such lengths to get unlocked iPhones? Part of the phenomenon, of course, is a testament to the power of Apple’s marketing might. There’s an interesting psychological study to be had on the effect of people watching Apple commercials!

Nobody does a better job than Apple at convincing the world that their products are must-haves. And let’s face it—the iPhone is pretty cool, as well as the symbol of a world in which just about everything we use gets smaller yet more powerful. The iPhone really does have everything you need in something that fits into the palm of your hand: all your music, all your contacts and the ability to find anything you want with a few touches.

Unlocked iPhones are handy, though, from a very pragmatic perspective, especially for those who travel overseas. Removing the SIM card allows users to put in a pre-paid card for a foreign provider whose rates are far less than AT&T or Verizon’s international rates.

These unlocked iPhones provide the best of both worlds—the chance to own an iPhone on your own terms and with the provider you want, not the one chosen for you. Look into buying one of these unique cell phones today!