Help with unlocking phone to GSM carrier

Is there a tutorial or guide to unlock the note 5 or do I have to pay these websites or someone from Craigslist. This seems to be like a secret people cashing in on. I had sprint recently took my services to metro pc now I have 3 useless phones. I might sell them if I can't get it to work on metro without a lot of trouble. I can't even find nothing on YouTube they all asking for money and I really don't trust any website with my cc information

Sent from my Z981 using XDA-Developers mobile app

from xda-developers http://ift.tt/2bWGrFb
via IFTTT