"I wish life was not so short," he thought. "Languages
take such a time, and so do all the things one wants to know about."
J.R.R. Tolkien, The Lost Road
Collecting Tolkien books is also like a never ending story: you'll never finish your quest, there will always be something new you like to have. Whether you are a collector wishing to get your hands on every single book ever written (try Songs for the Philologists, privately printed in 1936, 13 or so copies believed to exist; or the Leeds University Verse anthology from 1924 containing three poems by Tolkien), or you are simply trying to read everything he wrote, your quest will everytime seem endless.
Finding even a well-read copy of The Devil's Coach Horses (a discussion on a point of Anglo-Saxon translation) in the 1925 Review of English Studies Volume 1 Number 3 is going to be very hard due to the fragile nature of the object. And if you find one up for sale be ready to pay a lot of money.
Most people however, whilst admiring Tolkien's academic achievements, are primarily interested in The Hobbit and The Lord of the Rings. And since the last couple of years, Peter Jackson's movies have added an enormous amount of 'new' Tolkien collectors who are all eager to get their hands on as much precious Tolkien as possible. This of course changed the prices of collectible Tolkien books.
If you plan to collect the best known First Editions of The Hobbit (Allen & Unwin - 1937), The Fellowship of The Ring (Allen & Unwin, 1954), The Two Towers (Allen & Unwin, 1954), The Return of The King (Allen & Unwin, 1955) in fine or near-fine condition, you are going to need really a lot of money. For The Lord of the Rings, around €10,000-€17,000, and for a nice copy of The Hobbit, somewhere in the €20,000.
Still you do not need to despair since there are so many beautiful collectible Tolkien books out there which are easy to find and some very cheap. Among my favourites are the first editions of Farmer Giles of Ham, Smith of Wootton Major, The adventures of Tom Bombadil,...
To get you on the road, i made a complete section on collecting Tolkien books. First about what to collect, secondly a list of all the books there are, this can come out handy when going on your quest for books. Thirdly all places to go and buy these books, followed by some collector terms, sources and a list of rares i saw up for sale. I will only add really rare items. This list will hopefully become a profound source for info on the 'real rare' Tolkien books out there.