I was in the ultra-cheap German supermarket chain LIDL today and for GBP 4.99 I got a monitor which plugs into electric sockets and tells you how much electricity you are using and (when you've programmed it) how much it cost.
LIDL's somewhat eccentric special offers generally go quickly so if you want one of these you need to go to a UK LIDL this week. (I don't know if LIDL has these items elsewhere in Europe...though I suspect that their special offer policy is EU wide - eg beach things in summer, etc).
I also recommend LIDL to the "bunker" hoarders: their stuff is very cheap, some is horrible, but I can recommend French Comte cheese (like Emmental only half the price) a lot of their booze (German Beer Law: much respect!, and their hardware is often made in Eastern Europe and is of good material and workmanship, IMO.




