Today is, at least according to Kindle US, Tolkien Reading Day, and they have a selection of 19 Tolkien books on sale for today only. I spot checked, and many, perhaps all, are also on sale at Kobo US...
Here's the link to the Kindle US page, and I'm in a time-crunch right now, so you'll have to look at Kobo yourself...
Kindle US:
https://www.amazon.com/s?rh=n%3A7788141011&fs=true