Energy Cost Consumption By Device

I have read through so many different energy consumption costs forum entries, I have just completely become more confused. I am just looking for the following:

I have some Shelly EM devices hooked into larger power consuming devices and I am just looking to total the cost associated with each of these devices over the electric billing period. I have a fixed cost to my electric here in the US. The devices currently show up on the “Individual devices detail usage” on the Energy page as a W usage.

Honestly I would just be happy with the monthly consumption as a cost, if it is too complex to add billing periods. Start and end with the month.

I see a lot of entries on the forum outlining variable costs, gas, solar…all things I don’t need. Everything at my place is electric, stove, water heater, baseboard heating, AC, and I only consume.

Can someone please direct me to what I need to do on my home assistant to create this?