The Samsung Gear VR headset will start shipping on the 19th of August with the Galaxy Note 7, and you can pre-order the device on Amazon.com for $99.99 from now till the launch date. The headset is eligible for free shipping and is shipped and sold by Amazon.com, and comes with a gift wrap. It is known whether the price would increase after the launch date. It might be a good idea to grab it on pre-order now.
The full specifications of the Samsung Gear VR Headset can be found here.