Use sonos play 1's as chromecast audio's?

From what I can tell the only way to do this is by buying a Sonos Connect or Amp (which cost 300$+) just so I can plug a chromecast audio into it that sends it over the network to my play 1.

I wondering (since things like http://www.streamwhatyouhear.com/ and others can stream to Sonos’ just fine) if there wasn’t a way to have a raspberry pi or something else where I plug my chromecast audio in and then have that send it to sonos devices?