Buying a Iphone at Wal Mart. 1 cent?

So basically my mom purchased a plan a month or so ago, she has two lines on already both iphones. The iphones she got for.1$ each with the purchase of a contract. So my question is if she were to add another iphone to the plan would we still get it for.1$?

Yes. But since she is adding another line with text/talk/data… These are additional cost for the monthly payment