Not necessarily ‘bought’, more ‘repurposed something that was free’:
Sometime late last year, I applied for the free Octopus Energy plushy - ‘Constantine’
I chose to go for the big one instead of the little one, as the kids really like big plushies
It arrived yesterday and was a complete surprise!
Then while looking at this adorable soft-toy, I had a light bulb moment. Literally 
‘What if I stuck a Philips Hue bulb on it’s head and linked that to my Agile Octopus tariff via IFTTT - so I could place it somewhere like on the top of the fridge and it’d show if prices were currently good or bad?’
So that’s what I did…
Green = Prices good, OK to use washing machine
Red = Prices bad, don’t even think of washing clothes
Under pressure from the kids though, to return the adorable thing into a toy rather than an indicator.
RGB all the things