Amazon offers the 2nd-generation Amazon Echo Dot in Black or White for $39.99 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.98.) That's tied with last week's mention, the lowest total price we've seen for the general public, and best deal we could find today by $9. 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.
Of note, it's currently on backorder until December 27.