Groupon offers the factory-refurbished Google Chromecast Streaming Media Player, model no. GA3A00028A14, for $20 plus $3.99 for shipping. That's a buck below our mention of a new unit from three days ago, since expired, and $6 under the lowest total price we could find for a new unit today. It attaches to your HDTV's HDMI port and connects to your wireless network to receive streaming online video, music, websites, and more from your smartphone, tablet, or laptop. A 90-day Google warranty applies.