PSA: Don't buy the OnePlus 5 via Amazon (US)
If you didn't manage to pre-order a OnePlus 5 on the day of its announcement, and you can't make it to one of OnePlus' pop-up events, perhaps you're tempted to buy the phone via Amazon, seeing as it's available (in the US) via several third-party sellers. However, we certainly don't advise you to purchase the handset through Amazon, as this is not the official channel to get it from.
Right now, the US version of the OnePlus 5 - warranty included - can be found on Amazon for the insane prices of $779 (64 GB model), or $899 (128 GB model). The phone's international variant - without US warranty - is cheaper, but still more expensive than it should be: $559 (64 GB), or $639 (128 GB).
Obviously, you're better off if you're waiting until June 27, when the OnePlus 5 will be available directly from OnePlus' US website, warranty included. The smartphone's official prices are $479 (64 GB) and $539 (128 GB).