Apple on Friday introduced a SIM-free, unlocked iPhone 5s to its U.S. online store. Of course, this has also been available since day one, in the form of an unlocked phone that ships with a T-Mobile SIM card — simply pop the T-Mobile SIM out and pop another one in. This latest version ships with no SIM at all, allowing you to insert one for your GSM-compatible operator of choice. The phone starts at $649 for a 16GB model, which is the same price as the T-Mobile version. And you might want to buy that T-Mobile version anyway – the SIM-free phone shows an estimated 1-2 week wait to ship, while the T-Mobile model takes just 3-5 days.