Via select Alexa-enabled devices and for Prime members only, Amazon offers the second-generation Amazon Echo Dot in Black or White, bundled with a $10 Amazon Gift Card for $39.99 with free shipping. (Say, "Alexa, add an Echo Dot to my cart" to see this price at final checkout; link is for reference only.) Assuming you'll use the gift card, that's $10 under yesterday's mention, a low now by $10, and the best price we've seen. This voice-controlled device uses Alexa to play music (via Prime Music, Spotify, Pandora), control smart home devices (via Samsung SmartThings, Wemo, Nest), and do lots of other cool stuff (order a pizza via Domino's, order car service via Uber, play Jeopardy). It features 802.11n dual-band wireless, Bluetooth, and a 3.5mm audio output.
Note: This discount is available only on Amazon Echo, Dot, Tap, Fire TV, and compatible Fire tablet devices. You will receive an email confirmation typically within seven days of your purchase notifying you when the electronic gift card has been applied to your account.