The iPhone / Android cost difference is getting large
notes.kateva.org
notes.kateva.org
Additionally, the figures pointed out in this article are totals of the Voice&Data plans tied to the iPhones by AT&T. These are costs of a minimum iPhone service as deemed by AT&T, and not a cost of the iPhone itself.
Network-wise, the difference is in the billing backend, not in the towers or coverage.
Couple that with Google Voice (and the Talkatone app), and you can barely use cell minutes.