I’ve been trying out Roon with $35 (on sale) Google Home Mini speakers, to check the Chromecast features. Works like a charm. Interesting that the voice-control feature of the speakers also seems to be integrated; voice commands to the speakers like “Hey, Google, volume up” work and are reflected in the Roon Control app on my iPad. “Pause” and “Resume” work. “Stop” works.
Best Buy often sells their Insignia Google Assistant speaker on sale for $25, and it sounds better than the Google Home mini.
So, $25 for a Roon endpoint, all told. Including power, DAC, local volume and power controls, amplifier, and speaker/s.