The misprint in the list is the wand which is repeated twice (first listed in the beginning of the list and for the second time in the end of the list). But this kind of mistake is highly valued. If you have one of these 500 books then you can expect to be able to sell it for more than just few thousand dollars. One such book was sold at London’s Bonhams Fine Books and Manuscripts in November for around $33000.
The Head of Books and Manuscripts at Bonhams, Matthew Haley, explains why this small differences make the Harry Potter book value so much: “As the first book in the series, Harry Potter and the Philosopher’s Stone has a special place in the affections of the millions of readers across the world and the proof reading error about the wand in the first edition has, of course, become a treasured piece of Harry Potter arcana”.