You may remember that Amazon released the Fire TV set-top box this past April. That was definitely one of the highlights of my career. I'm thrill to say that we just announced the Fire TV Stick this morning!
The Fire TV Stick is similar to the Fire TV in terms of functionality but has a smaller form factor. At only $39 each, the device is cheaper than the Roku and Chromecast. Though it starts shipping in November, you can pre-order it right now. On top of that, Amazon Prime members can get the Fire TV Stick for $19 - which is less than half price. Just make sure to be quick as the Amazon Prime deal only lasts two days. :-)
Disclaimer: Amazon did not pay me to make this post. I only speak as a user.