You're not really supposed to know about this because Apple
isn't advertising it, and heck, it might not even be true. But word on the Web is that Apple's retail locations have authorized employees to price match discounted iPhone 4 and 4S models, provided the lower price is from a major retailer or wireless carrier. In other words, Apple isn't going to price match that $25 iPhone 4S Ed from the down the street is trying to hawk from his trench coat, but if Best Buy or Sprint advertises a stellar deal, you're golden, Ponyboy.
There is a limit. According to the source who revealed the secret policy and internal screenshot to MacRumors
, Apple is willing to knock up to $49.01 off the price of an iPhone, and not a penny more. Don't expect Apple employees to bring it up, either. You'll have to request the discount, and likely name your source; maybe even show proof, like a flyer. Based on the screenshot, Apple will honor price reductions from Best Buy, Radio Shack, Target, Sprint, and "Carriers," a category Sprint apparently doesn't fall into.
Also note that this applies to in-store purchases only and not online orders. All that said, this could be a way to score a nice discount on a great smartphone (put away the pitchforks, Android users), as vendors look to unload existing inventory in anticipation of Apple's upcoming iPhone 5.