Crutchfield offers the Sonos Play:1 Wireless Speaker Starter Kit in Black or White for $349 with free shipping. That's the lowest total price we could find by $49. It includes two Sonos Play:1 Wireless Speakers which can be paired for a stereo image or used independently for a multi-room audio solution. Connected via your home WiFi network, they stream internet music stations (Pandora, Spotify, TIDAL, and more) as well as network-based music files.
Update: PC Richard charges a buck more.