Amazon is currently running a "buy three from this list, pay for just two" sale, which has a good number of Tolkien items in it:

https://www.amazon.com/promotion/psp/ANQ8E78JXZ53U?ref=psp_pc_atc&redirectAsin=0618512659&redirectMerchantId=ATVPDKIKX0DER

I do not know how long this promotion will be running, but there are some great prices at the moment (even before the free book offer)

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Letters From Father Christmas
Tolkien, J.R.R.
0618512659
(Paperback)
$15.11
Availability: IN_STOCK_SCARCE
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The Silmarillion: Illustrated by J.R.R. Tolkien (Tolkien Editions)
Tolkien, J. R. R.
0063280779
(Hardcover)
$30.50
Availability: IN_STOCK
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J.R.R. Tolkien 4-Book Boxed Set: The Hobbit and The Lord of the Rings: The Hobbit, The Fellowship of the Ring, The Two Towers, The Return of the King
Tolkien, J.R.R.
0345538374
(Mass Market Paperback)
$28.07
Availability: IN_STOCK
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Pictures by J.R.R. Tolkien
Tolkien, J. R. R.
0358653045
(Hardcover)
$unknown
Availability: OUT_OF_STOCK
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Tolkien Fantasy Tales Box Set (The Tolkien Reader/The Silmarillion/Unfinished Tales/Sir Gawain and the Green Knight)
J.R.R. Tolkien
0345466462
(Mass Market Paperback)
$16.65
Availability: IN_STOCK
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The Making of Middle-earth: The Worlds of Tolkien and The Lord of the Rings
Snyder, Christopher A.
1454944757
(Hardcover)
$13.72
Availability: LEADTIME
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The Complete Tolkien Companion
Tyler, J. E. A.
9781250023551
(Paperback)
$17.93
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The Art Of The Lord Of The Rings By J.r.r. Tolkien: The Complete Collection of Illustrations, Maps, and Sketches from Middle-earth
Tolkien, J.R.R.
0544636341
(Hardcover)
$26.68
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A Hobbit, a Wardrobe, and a Great War: How J.R.R. Tolkien and C.S. Lewis Rediscovered Faith, Friendship, and Heroism in the Cataclysm of 1914-1918
Loconte, Joseph
0718091450
(Paperback)
$10.99
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J.r.r. Tolkien: A Biography
Carpenter, Humphrey
0618057021
(Paperback)
$15.18
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The Languages of Tolkien's Middle-Earth: A Complete Guide to All Fourteen of the Languages Tolkien Invented
Ruth S. Noel
0395291305
(Paperback)
$14.18
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The Epic World of Tolkien: A Coloring Book
Editors of Thunder Bay Press
1645174581
(Paperback)
$17.12
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John Ronald's Dragons: The Story of J. R. R. Tolkien
McAlister, Caroline
1626720924
(Hardcover)
$13.99
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The Fellowship: The Literary Lives of the Inklings: J.R.R. Tolkien, C. S. Lewis, Owen Barfield, Charles Williams
Zaleski, Philip
0374536252
(Paperback)
$10.64
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A Secret Vice: Tolkien on Invented Languages
Tolkien, J. R. R.
000834809X
(Hardcover)
$26.99
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J.R.R. Tolkien: Artist and Illustrator – A Definitive Art History of the Middle-earth Paintings and Sketches
Tolkien, J.R.R.
0618083618
(Paperback)
$19.85
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Tolkien and the Study of His Sources: Critical Essays
0786464828
(Paperback)
$18.99
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Understanding The Lord Of The Rings: The Best of Tolkien Criticism – The Definitive Collection: Fifty Years of Essays on Middle-earth
Isaacs, Neil D.
0618422536
(Paperback)
$12.99
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