Abe Books 
AbeBooks is an online marketplace for books. Millions of brand new books, used books, rare books, and out-of-print books are offered for sale through the AbeBooks websites from thousands of booksellers around the world. Readers can find bestsellers, collectors can find rare books, students can find new and used textbooks, and treasure hunters can find long-lost books.
Here is where you can find Young Adult fantasy books that are rare:
You won’t believe the cool books you can find here!