Amazon has the Oculus Touch Controllers [amazon.com]
, which includes a camera sensor, for $85. If you recently got the oculus rift + touch bundle, this might be a good option to get a third sensor and have backup controllers. The sensor by itself is $60, and this is only $25 more.
You can't currently use more than 2 controllers at a time, but there's alpha support [reddit.com]
for a third controller for developers to be used as a mixed reality camera. And having a second pair of controllers for $25 is a pretty good deal in case you ever damage a controller.
Note: The $60 sensor comes with a 15ft (5m) USB 2.0 active cable extender, but this touch bundle doesn't. However, if you need a longer cable or wish to get a USB 3.0 extender, you don't lose much getting the touch bundle.
For what it's worth, I didn't have to pay tax on this item. I usually pay tax for Amazon purchases (for example, the $60 sensor, which does
charge tax), so it was a nice bonus. And free same-day shipping for Amazon Prime members.