Yeah. Those would be super useful as general purpose displays. I found something on Alibaba without much technical info about.

Hopefully someone gets the idea and mass produces it.

https://m.alibaba.com/product/60250435288/Supermarket-esl-di...

yeah, I wish there was an easy DIY way to program those

order enough of them and i expect you could get one of the sellers to give you specs. they just use 433MHz; shouldn't be too hard to talk to them once you know what to send.

I was able to find them here for cheap: http://www.pervasivedisplays.com/products I have no relation to them, there might be better distributors, and I have not ordered these. They are available via Digikey

Oh, wow! I did not know those were a thing. Given the volume that supermarkets will be buying them, those will get affordable quick.