QuoteAT&T will begin offering the iPhone 3G phones at its retail stores beginning July 11 at 8 a.m. local time. AT&T is the exclusive iPhone carrier in the United States. Under its offering, the lower price will be available to only customers who purchased an iPhone before July 11, or are activating a new customer line with AT&T, or are eligible for an upgrade at the time of purchase. Customers also are required to sign a two-year contract. AT&T customers who are not eligible for an upgrade discount can buy the iPhone 3G for $399 for 8GB model, or $499 for a 16GB version, under a two-year contract. Customers who purchase the phone without a contract would pay $599 for 8GB or $699 for a 16GB.