If you'd like a cheaper alternative (and don't mind a little DIY) I wrote a library that lets you render HTML onto low cost ePaper displays using a Raspberry Pi.
It would be pretty easy to modify the chain of command to have the backend start and stop the Chromium process. I haven't taken any detailed measurements, yet, but I'm guessing simple web pages like the example weather dashboard aren't too CPU intensive to render.
https://github.com/samsonmking/epaper.js