I believe scorpio1973 is correct.
Full retail is $649 for 16GB, $749 for 32GB and $849 for the 64GB. That would be the only way to get it unlocked out of the box.
Getting it from Apple direct is safest but my friend got his from an at&t store and it was unlocked (he paid full retail price).
I am just surprised people are not talking about it on the forums since there is a way to get an unlocked phone now without waiting for Apple to start calling and selling them as such. iPhone 4S Device Only (SIM unlocked) became avail from Apple's web site/ stores officially a couple of months after the launch. I would expect the same for the 5.
The way to tell if you have an unlocked phone is when you take it out of out of its box to just plug it into iTunes (without turning it on). It will boot, be detected by iTunes which upon checking for the IMEI # on Apple's servers will display:
"Congratulations, your iPhone has been unlocked".
Other method is: Turn on the phone, swap the SIM for a different one from your carrier, plug it in and iTunes will also do the same.
Though this method may be more difficult to execute since nano SIMs are not that easy to come by right now.