The 15GB Mobile Share Value plan as well as the different kinds of device access charges will amount up to approximately $100 each month, according to AT&T. This particular offer will be made available to AT&T customers who happen to be subscribing to Mobile Share plans that carry 10GB of data right from the get go, and for new customers, you too, will be able to enjoy the additional 5GB of data for free by picking up the same plan.
AT&T hopes to roll out this deal from tomorrow onward, but they have coyly remained mum as to how long this particular deal will be made available for, so I would venture to say that the early bird gets the worm in such a case.