Until now, Apple required that you choose your carrier model when purchasing the latest iPhones. That meant the phone would be activated on the network provider you selected at time of purchase and would also include a SIM card.
That's great for folks that are happy with their carrier and don't really plan to switch.
It's not so good for business globetrotters who pick up local SIM cards during their travels, which is often far cheaper than any international voice or data plans provided by U.S. carriers.
Of course, expect to pay full retail price for your new iPhone, which starts at $649 for the base iPhone 6 and tops out at $949 for a 128 GB iPhone 6s plus. The unlocked model works with a nano-SIM from all four major U.S. carriers.
It doesn't appear to me -- or at least I couldn't find mention of it -- that the SIM-free unlocked iPhones can be bought through Apple's iPhone Upgrade Program.
However, you can finance the device through PayPal Credit at 12.99 percent or opt for a new Barclays Visa card with Apple Rewards that carries a one-year, interest free promo period for new purchases totaling $499 to $998.