No. If you do that and cancel within the first thirty days, you are required to return the phone. If you cancel after thirty days, you will be charged a $375 early termination fee.
If you're not eligible for an upgrade, you are able to buy the iPhone directly from Apple or AT&T and pay the full retail price ($599 for the 16 GB version, $699 for the 32 GB version).
If you're not eligible for an upgrade, you are able to buy the iPhone directly from Apple or AT&T and pay the full retail price ($599 for the 16 GB version, $699 for the 32 GB version).