Is the iPhone 4S really free?

Okay now that the iPhone 5S and 5C is out I was on he AT&T website and it says the iPhone 4S is free with a Two-Year Contract my my Sister want's to put me on her plan for my Birthday gift and she has one more spot left on her plan and if she puts me on it will the iPhone 4S be free since she has a contract with AT&T or will there be like a 50 dollar Fee?

I don't know

It will be free for you not her.basically since you are signing up for a 2 year contract the phone will have your phone number on it not hers.anyway its not really free because you are signing a 2 year contract with the phone service so each month you pay like 60 $ for data service and the phone. $60x24months thats over $1300.by the way iphone 4s has been "free" with contract since last year

The phone itself is free, but you'd still have to pay things like the activation fee & of course the plan options.