I got this energy monitor free from E.on around 10 years ago. I changed tariff a few times with them, then switched to Bulb, and am now half way through a 2 year fix with EDF. It was very easy to set up initially and each time I change tariff I enter the new rates. It isn’t switched on all the time, only when I’m inclined to check something specific. It’s only shortcoming is that the clock is slow, around 5 minutes behind within an hour of resetting it, but it’s unnecessary to the function anyway.
I’ve had it on this morning:
1. The ancient fridge-freezer running
2. The fridge-freezer switched off
3. The broadband router switched off
Always on at the mains are two Echo smart speakers, three Tapo smart plugs (Sky box, tv and a table lamp), and the main switch for the boiler (programmer, pump, 3-way valve, and wall thermostat). Everything else, apart from the fridge freezer, is unplugged or switched off at the wall.