If i get an at&t iPhone 5 will i be able to unlock it without startup?

Unlock means that it can run any carrier. This is because at&t need some billing zip code(can someone tell me what's that) and social security number… I'm getting it from someone i don't know so i can't get it maybe…

You can get it unlocked here: http://gsmunlocklabs.com/unlock-iphone/

Can't unlock att iphone 5.