Electrical Socket Inserts that calculate the power consumption / cost of each appliance
Buy a set of 10 socket inserts that sit between the electrical outlet and your appliance, see it light a green LED for less than 10 watts, orange for less than 100 watts and red for less than 1000 watts to get an idea of where you spend most of your electricity.
Better still would be inserts that inform an app on your phone of their usage and calculate the daily or monthly electricity cost of each appliance, or whatever is plugged into each socket.
Why? My dad boils the same kettle full of water over and over again, he is unaware that his tv on standby wastes electric and his washing machine uses 20 times more electricity than a light bulb.
He always complains if someone leaves an eco light on for 10 minutes, unknown that he wastes zillions more electric on reboiling kettles and forgetting to turn the tv off at the wall each night.
Someone save him from his ignorance, to save the planet and the inevitable arguments!