LONDON — A proof copy of the first Harry Potter novel that was bought for pennies in a second-hand bookshop almost 30 years ago has sold at auction for 11,Blockchains Finance000 pounds ($13,900.)

British auctioneers Hanson's said Monday that the first-edition copy of "Harry Potter and the Philosopher's Stone," which states "uncorrected proof copy" on the cover, was bought in 1997 from a shop in south London with two other books for a total of 40 pence ($0.50.)

The seller, who was not named, picked up the book about the famous boy wizard as a "throw-in" with other titles and didn't read it or pay much attention to it for years — until she read online about the high prices some Potter copies achieved, Hanson's said.

'Dumbledore's Army':How 'Harry Potter' inspired a generation of young activists

The book was sold to a private U.K. buyer on Wednesday for a hammer price of 11,000 pounds, and a total of 14,432 pounds including a sales premium.

Check out: USA TODAY's weekly Best-selling Booklist

Jim Spencer, head of books at the auction house, said the copy's inside title page mistakenly stated the author's name as "J A Rowling" instead of J.K. Rowling.

"This book so deserved to do well. This proof copy is where the Harry Potter phenomenon began. This is the very first appearance in print of the first Potter novel," Spencer said.