I bought a Nokia Lumia 520 go phone from a Microsoft store while holidaying in Hawaii. Upon asking the question if this is a locked phone i was repeatedly told that the phone is not locked and I can insert any other carrier's SIM on it. The packaging is not clear on the locking status. Raised a couple of Device unlock requests. I am back in India the country that I live in and am unable to use the phone. I would request if AT&T can provide an official unlock. I am also willing to pay any residual amount. The package is misleading to international buyers and the store personnel did not clearly understand the product and whether it is locked.... Are they assuming that everyone is an AT&T subscriber?
Nice choice in phones Manish I used a previous model Nokia before my current phone and it was a pretty solid device (Nokia Lumia 900).
So the easiest way to tell right away if you are buying a locked or unlocked device is where you are buying it from. Generally speaking if you buy a phone from a carrier directly (AT&T, Verizon, Tmobile) you are buying a phone stamped with that brand and locked to that carrier.
Now factory unlocked devices exist but are primarily bought directly from the manufacturer. So for example you want a unlocked new iPhone 5s, for this you would buy it from Apple directly. Then you can use it with whatever Carrier you want (that also supports the 5s phone).
The good news is AT&T does allow you to unlock your devices as long as you meet certain requirements. I had my Lumia 900 unlocked after about a year of using it on my GoPhone account. You just have to head over to this link: