Do I pay for the Internet when I'm not home?

I got an iPhone from AT&T and I got unlimited so does that mean I don't have to pay for the Internet I use when I'm not home or do I still have to pay for that. I know I don't have to use the Internet I use when I'm home but I'm confused if I have to use when I'm not home?

You can go to an Apple store, and ask them to explain to you what you have, and how you can use your IPhone.