Ask HN: How Much a Chromecast Really Costs?

The actual question is how much electricity does a Chromecast consume? Google's Chromecast has no on/off switch, it is always casting, either your feed from a device, or an infinite loop of Google (publicly available) Photos. If Screen's input channel is set to that HDMI, you see it, if not, you don't, but it is always casting. I have zero knowledge about electricity / physics and can't tell the different between Ampere / Watts and Volts, and would love to get a proper answer to this. THANKS IN ADVANCE.