Before it was part of the most popular children's series on Earth, Harry Potter and the Philosopher's Stone was a new book from an unknown author from the UK. Only 500 copies of the first edition were printed, and 300 of them were donated to libraries. Today, early prints of the title are worth serious money. Edinburgh Evening News reports that one copy sold for approximately $90,000 when it went to auction on March 28.

Before the 1997 copy of book one in J.K. Rowling's Harry Potter series was sold through Bonhams auction house on Wednesday, it was estimated to be worth between £40,000 and £60,000, or $53,000 and $79,000. A private collector from the U.S. ended up bidding £68,800, or roughly $90,000, to bring home the item.

This wasn't just any copy of Harry Potter and the Philosopher's Stone. It originally belonged to Christopher Little, J.K. Rowling's first literary agent, and includes a sticker with Rowling's signature. It also features several errors: Harry's school supplies list says "1 wand" twice, the title is misspelled on the back cover, and the number sequence on the imprint page is incorrect.

Rare quirks—like misprints or notes from the author—make Harry Potter books especially valuable, but early copies may still be worth money without them. If you have a U.S. or UK first edition of the first Harry Potter book leftover from your childhood, it could net you thousands of dollars.

[h/t Edinburgh Evening News]