In the (relatively) new energy dashboard it will show detailed breakdowns of energy consumed by hour, day, month, etc. It would be useful if we could break down cost in the same way. Due to TOU and other factors cost is not a linear function of kWh used.
It would also be useful if the little flyout that shows up when you hover one of the bars in the bar graph showed the cost for the energy used in that time range.
Additional thought: Cost can be put in the same graph as usage, as f.ex. a line or even a second column with a different color.
We’re in a time of wildly varying energy costs, so knowing exactly how big the difference is for each hour is a must with me 
I would love to have a extra line over the energy usage chart showing the hour tariff.
As I have it now I have a entity that stores the tariff each hour and then I just use a statistic chart to display it in a card.
Optimal would to have it overlayed as a line on the energy usage chart, that way I can fast and easy see exactly how I used my power and at what tariff.
I guess if displaying like week/month/year it would need to average the tariff?
Maybe a setting to display the cost (sum of costs) and/or tariff (average tariff) for each data point.
Example picture for visualization 
