If you're after a carrier-specific iPhone 5, the US Apple Store's online site says that you should wait three-to-four weeks from now, but a quick search on Apple's website may have accidentally unveiled a bunch of pricing on factory unlocked iPhone 5s.
It was tripped up by AppleInsider reader Dhaval Dinani, confirmed independently, and is now making the news rounds. The units are definitely not official, and could just be placeholders in Apple's database. But, the prices are consistent with identical models being sold in Canada, where all iPhones are unlocked.
We should expect the 16GB, 32GB and 64GB unlocked iPhones to have prices of $649, $749 and $849, respectively. AppleInsider expects the new unlocked iPhone 5s to be sold when the supply constraints begin to improve.