I can throw in a link which you may or may not find interesting:
Some of the rule code posted here you may find inspirational since the Tibber binding has a similar channel for providing prices in JSON format as the original rules posted here used.
I’m interested in finding the best approach for creating automations and other things around energy prices. I didn’t look into aWATTar previously, so will give it a look. Can you give some examples of the use cases you see in the Bestprice thing approach? I believe you still need to write rule code, or can you actually automate something fully using UI with this?