How to factory unlock my tmobile iphone 5?

How to factory unlock my tmobile iphone 5?

You will have to take it into T-Mobile.It'll cost you about $20-25

You can do it yourself, but in the end it'll still cost you money to get a key.
Unfortunately it's not like blackberry or other phones.

their is the option of Jailbreaking the phone and doing a software unlock however.
But this will reset/lock if you ever update your iOS version. So it's not the best option
but it's free.