IPHONE 4S UNLOCKING

Need help finding out how to unlock an iphone 4s from t mobile to any network?
Asked t mobile but they want £30 and it will take a month
Anyone know how i can get it done cheaper preferably free lol or know how i could do it myself?
Any advice most welcome

This worked for me, but apparently only works 90% of the time.

Could give it a go mind.

http://www.youtube.com/watch?v=mB_L5gi94Cc