Apple's online store is now offering SIM-free iPhone 6s and 6s Plus models. Pricing for the former starts at US$649 ($32.45 with Apple's iPhone Upgrade Program). Pricing for the latter begins at $749 ($37.45 per month with the upgrade program.
"The SIM-free iPhone comes without a wireless contract commitment or carrier financing. It doesn’t come with a nano-SIM card for iPhone 6s, iPhone 6s Plus, iPhone 6, iPhone 6 Plus, or iPhone 5s," says Apple. "And because it’s unlocked, it isn’t tied to one carrier, so you can get a nano-SIM from any supported carrier worldwide, such as AT&T, T-Mobile, Verizon, or Sprint in the United States."
Of course, the plan also means that you have to pay the full price for the Apple smartphone upfront. On the bright side, SIM-free iPhones work on a variety of networks including AT&T, Verizon, T-Mobile and Sprint in the U.S. International support is also available via the iPhone's multi-band LTE radio