Apple is now selling contract-free iPhone 6 and iPhone 6 Plus in its stores and online. The 16 GB base model iPhone 6 will costs you $650; the iPhone 6 Plus starts at $750.
Unlocked iPhones can be activated for use any carrier—AT&T, Sprint, Verizon or T-Mobile. They ship in 3-5 business day (compared to 1 for those subsidized by carriers). This arrived SIM-free unlocked iPhones is a little later than usual—perhaps a result of relatively low supply. [Apple]