How to know if an iPhone 5 is unlocked?

I'm planning to buy a iPhone 5 on craigslist unlocked, how can i check whether its locked or not before i give him/her the money?

It doesn't matter just unlock it through itunes on the computer

Bring your carrier's sim card with you and ask the seller if you can try it on the iPhone. If not, I'd advice you not to buy it because they might be scamming you.

Verizon iphone 5 are all unlocked.
if its att or sprint, bring 2 sims from diff carriers.

You can insert your sim card and call someone. If that works then it is unlocked.

I have found the way to unlock at&t iPhone 5, wanna try? Following this page i given…

You should ask these guys
http://jailbreak4iphone.com/