The Chromecast Audio is the cheapest ever by $7 according to PrivceSpy.
Stream your favorite music with Google Chromecast Audio. Simply plug into your speaker's auxiliary input and connect to your Wi-Fi network. Then just tap the Cast button from your favorite apps on your phone, tablet or computer to cast songs, radio stations and podcasts to your speaker.
Plugs into your speaker for streaming music through Wi-Fi
Works with devices iPhone, iPad, Android phone and tablet, Mac and Windows laptop, or Chromebook
Search, play, pause, queue songs and change the volume right from your smartphone
Interruption-free listening
Control music from anywhere in the house
1 Year warranty
Use coupon MYNL16W10 $10 off $100. Also use the free shipping code FREDE4ME
An ok deal, if you get two :)