Is unlocking an iPhone illegal if i do it for money?

If i offered a service to make the iPhone unlocked from its carrier, would it be illegal to do that?

No sir/ma'am. You are free to do so, but you will have to abide by the unfortunate circumstances if anything happens to your phone.

No, all you're doing is changing the software on the phone. It might be against a select providers terms and conditons but there's a big difference between that and being illegal. A lot of providers will actually unlock it for you if you ask them.