Is it legal to pay someone to unlock an iPhone?

I'm just really curious because now that the iPhone 5 is out, iPhone 4S is much cheaper, and iPhone 4 is free on AT&T. I have T-Mobile so I feel really left out. I have an Android, Motorola Defy, but it just doesn't seem as great as when I had an iPod Touch, so clearly iPhone would be even better than that! I've been looking online and noticed on some sites like Craigslist that people unlock iPhones for really cheap. So I was thinking that instead of buying one from Apple for over $500, that I buy one for $99 then pay someone to unlock it for about $20. I was thinking this could be my answer for a T-Mobile iPhone, but I don't know if it's legal to do since Apple didn't approve of it being unlocked for me. So if I did get it unlocked, but then something bad happens and I need to send it back, would I get in trouble! Can someone please help?!~

It's completely legal to unlock and to jailbreak it. The only way that its illegal if you jailbreak it and then download cracked paid apps for free from installous, but even then, it'll be almost impossible to get caught.

AT&T stores will even unlock your iPhone for you at the end of your 2 year contract if the phone is at least 2 years old.

Its not illegal but apple might refuse service if anything happens to it

There's no such services.
only the original carrier can unlock an iphone 4s.

It's legal, but it would most likely void any warranty on the device itself.

No it is not illegal.