I am planning to buy either an iPhone 4 or 4S (not really keen on next iPhone for now). I figured out that factory unlocked iPhone 4/4S go for substantially higher price (used) on the usual websites like craigslist / ebay etc while the AT&T locked ones are lower. Now i want the iPhone to be factory unlocked before i buy or have to get it unlocked after i buy a locked one as i intend to use it outside the USA. I am not an AT&T customer and never was so i am pretty sure that if i buy a iPhone4/4S from ebay etc and tell AT&T to unlock, they will not entertain me. But i do find several listings on ebay and craigslist where people offer getting permanent unlock for the iPhone 4/4S for 15$ and around. How legitimate these listings are and do they work ? Can i buy a used AT&T iPhone 4/4S and use these services from ebay / craigslist etc to get a permanent unlock, thus saving good amount of money vis-a-vis buying a factory unlocked iPhone 4/4S ? One such listing is this.. http://www.ebay.com/itm/ATT-AT-T-UN...737?pt=LH_DefaultDomain_0&hash=item2ec1534de9 Please tell me if what i am planning to do is feasible ? I do not want to end up with a locked phone which i cannot use.