Groupon offers the factory-refurbished Google Chromecast Streaming Media Player for $20. Coupon code "HOT3" cuts it to $18. With $3.99 for shipping, that's $2 under last week's mention and $8 under the lowest total price we could find for a new one. 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. Deal ends July 21.