Recommendation for Endgame Study Book for 1200 Player

I think "Chess endings: essential knowledge" by Averbakh is the best endgame book for beginners.
But it has a drawback: it is quite expensive for such a short book!
I'm surprised that it was mentioned that Chess Endings: Essential Knowledge is expensive. I chose it specifically because it was the cheapest endgame book I could find. It's 15 euros on the German Amazon. I just quickly checked the American Amazon (your profile says you're from the US), where it is US$11 brand new. You can also get chess books a lot cheaper if you get them second-hand. You might find someone trying to give away a box of chess books in your area of you look.

This will serve you at the beginning level until your are high rated . . .
Make sure you use a board, even if it looks like you can just read it . . .
By the way there seems to be a shortage of this book, but Samzon just got some . . .

In all probability you will learn how to mate with a Queen, Rook, 2 Rooks. . .
Promote a Pawn . . .
What ever the book teaches learn it because you will use it your whole chess life . . .

Dr. Reuben Fine's "Basic Chess Endings"

Reuben Fine's 'Basic Chess Endings' was my second chess book after Walter Korn's 'MCO 11' neither of which I'd recommend as a means of study today.
For endgames 'Fundamental Chess Endings' by Karsten Muller & Frank Lamprecht
For your first chess book 'The Mammoth Book of Chess' by Graham Burgess' which covers everything.

I have used Fine's endgame book since the early 70s.
I've had my Fine's Basic Chess Endings since the early 1970's too, no doubt its a good book and to think Fine did all those calculations in 1930's/1940's before computers! Not used Fine's book recently but I do use the games half of which I have in a Chessbase database. My go to book on endgames is Muller & Lamprecht's Fundamental Chess Endings which covers the same material as Fine but with more notation, better layout, larger print, larger diagrams and algebraic notations all of which makes it an easier to follow book.
Graham Burgess's Mammoth Book of Chess is a no brainer as a first chess book it covers everything chess.

What about a free pdf download?
Fundamental Chess Endings here [linking to copyrighted works not allowed -- VP]
and more free chess books than you can shake a stick at. Sadly The Mammoth Book of Chess and Basic Chess Endings isn't on the list :-(
Dr. Reuben Fine's "Basic Chess Endings"
"Basic chess endings" by Fine is not for beginners. Chapter 1, and section 2.1 are beginner-level, but they are covered in ten pages (the book is almost 600 pages long!). I guess some other sections or examples are suited for beginners, but they are scattered.
I would not recommend it to player rated around 1200.
I'm surprised that it was mentioned that Chess Endings: Essential Knowledge is expensive. I chose it specifically because it was the cheapest endgame book I could find. It's 15 euros on the German Amazon. I just quickly checked the American Amazon (your profile says you're from the US), where it is US$11 brand new. You can also get chess books a lot cheaper if you get them second-hand. You might find someone trying to give away a box of chess books in your area of you look.
I think it is expensive for a book that has just slightly more than 100 pages.
Silman's book, mentioned in this thread, is just a little more expensive, and is over 500 pages!
Of course, it is not only quantity that counts, but also quality (nobody wants 500 pages of rubbish). Averbakh's explanations are excellent. I have not read Silman's complete endgame course; but I have read other books by him, I have a positive impression of his chess writings and would expect a very good product.
Reuben Fine's 'Basic Chess Endings' was my second chess book after Walter Korn's 'MCO 11' neither of which I'd recommend as a means of study today.
For endgames 'Fundamental Chess Endings' by Karsten Muller & Frank Lamprecht
For your first chess book 'The Mammoth Book of Chess' by Graham Burgess' which covers everything.
I consider the Mammoth Book of Chess to be the best $12.95 (as then it was) that I ever spent. Covers the whole range of chess topics, and all in substantial depth. Easy for the beginner to learn from, but with deep concepts which will continue to aid a player as they improve.
An excellent choice for someone around the 1200 level. It will serve you well for years.

Back when I was a very active OTB player, RHM Press published "Practical Chess Endings," by GM Paul Keres. It is a good primer. My first edition (1974) is in EDN, but I understand there is a newer Algebraic efition available.