Unlock AT&T iPhone before selling to Amazon?

[wlow3]

I've heard one can get a bit more if an iPhone is unlocked before selling it back, say, to Amazon (etc.)

My understanding is that one can contact AT&T and they will unlock the iPhone. (I've since moved on with a new iPhone 6s with a two year contract. My old iPhone, a 5s, is no longer under contract nor has cellular service.)

What does "unlocking" do if one is supposed to pull out and keep the AT&T SIM card before selling an iPhone? Is this what you'd recommend doing, or is it not worth it and should I just sell it back to Amazon as a locked AT&T phone?

 

[IowaLynn]

I sold an AT&T Samsung S6 to Amazon and it looks like the difference in trade-in price is tiny. Reset the phone and send it in. You can opt out if the price isn't a minimum desired. Amazon offered $100 more than if I took or sent it back to AT&T.

 

[Givmeabrek]

Just check with Amazon and see what the difference in price is. You can submit on the AT&T website for an unlock and they will do it for free. Unlocking will allow the phone to used with a different carrier or even overseas. Your choice.