Hello, I have an iPhone 4S and my carrier is AT&T. I was wondering if there is an extra cost for mobile hotspot if I have a 6GB mobile data family share plan. I have looked it up and believe that with my plan it is free, but would like to be sure because it seems that it may cost me $20 if my plan does not include this particular service. Thank you for any help, and can you please link me to any sources you find.