Iphone 4S (IoS 6.1.3): possible to UNLOCK?

If so, how? What steps do I need to take? I heard something about Jailbreak and then Cydia? Do I jailbreak the phone then use whatever Cydia is to unlock it? If not, then how can it be done?

The original carrier can unlock it for free.

Yes of course it is possible to unlock. For this you can visit the best repair shop of iPhone. They are really fast about this unlock system. If you want then you can try that, I think it will be the best solution.