How to jailbreak and unlock an iphone 4 ios 6.0.1 for free?

I recently bought an iPhone 4 for AT&T and I want to unlock it for T-mobile. Is there anywhere or any site that I can learn to do it for free?

Hi, check the following guide for learning how to officially unlock an iPhone, I wouldn't recommend any other way: https://www.fastgsm.com/en/page/how-to-unlock-iphone

There are many websites and youtube videos to show you how to jailbreak the iPhone. Jailbreaking does not allow you to easily update your iOS though and it isn't technically a permanent unlock like a factory unlock. Since your iPhone is an AT&T locked iPhone the best and cheapest way to unlock is a factory unlock site like iPhoneUnlockedCheap.com or many other reputable providers. A factory unlock also does not need to modify the software on your iPhone (risky) like a jailbreak.