Apple has made unlocked versions of the iPhone 6 and iPhone 6 Plus available on its web site. Customers can now choose to buy their iPhone without a carrier commitment. The unlocked models support GSM-based networks such as those operated by AT&T and T-Mobile. They can also be used on networks in other countries. The unlocked models cost the same as standard models. The 16GB unlocked iPhone 6 costs $649 and the 16GB unlocked iPhone 6 Plus costs $749. Consumers can opt for higher capacity models if they so wish. The unlocked models are sold without SIM cards.