The Hobbit by JRR Tolkien probably doesn’t need any explanation, but just in case (!!!), here’s a link to its Wikipedia page. Although I actually have to disagree with Wikipedia, which calls it a children’s classic – I think it’s just a classic. But in any case, The Hobbit is on sale today (March 25, 2021) in both the US and the UK, although the sale price is much better in the UK (£0.99) than in the US ($2.99). But it’s worth it at either price!
A word of caution – there are mulitple editions, so make sure you use the links below, and verify the price before you buy.
Tolkien’s Unfinished Tales is £0.99 as part of today’s Daily Deal at Kindle UK: https://www.amazon.co.uk/dp/B002RI9ZYK
An omnibus of all three Lord of the Rings titles (The Fellowship of the Ring, The Two Towers, and The Return of the King) is on sale today at Kindle US for $4.99, which is a pretty nice price if you don’t have any of the three already…
The Lord Of The Rings: One Volume
Kindle US: https://www.amazon.com/dp/B007978OY6