Even as The Walking Dead #104 arrived in stores Wednesday, a mint copy of the first issue of the acclaimed horror series sold for $10,000 on eBay.

Characterized by the seller as "the holy grail of comic books," the slabbed copy is graded 9.9 out of 10 by the Certified Guarantee Company, "the highest grade of this book in an extremely low print run."

While many would argue whether the October 2003 first issue of The Walking Dead trumps, say, Action Comics #1 or Detective Comics #27 as "the holy grail of comic books," it did have a pretty low print run: Image Comics Publisher Eric Stephenson revealed this year at the Chicago Comic & Entertainment Expo that initial orders for the comic by Robert Kirkman and Tony Moore "totaled a mere 7,300 copies."

"The Walking Dead came in dead last out of the half dozen new titles we launched that month," he told the crowd at the Diamond Retailers Summit. It was beaten by Cursed #1, Battle of the Planets: Manga #1, Sword of Dracula #1, Something Wicked #1, and Realm of the Claw #1. I don’t know about the rest of you, but I was actually working at Image back then and aside from the Dracula book and the Battle of the Planets book, I don’t even the vaguest recollection of what those other books were about. And I don’t say that because they were necessarily bad, but because they’re not around anymore."

Ten years later, of course, the property is a media franchise, with a hit television series, video games, a magazine, toys, clothing and more. The comic is also a sales juggernaut, with July's landmark 100th issue setting a new record for the highest orders for a comic in a single month (an estimated 366,000 copies in the direct market alone). The collections are consistent bestsellers in both bookstores and comics shops, with the first volume making routine appearances near the top of the charts, more than eight years after its initial release. In his analysis of 2011 bookstore sales, retailer and Comic Book Resources columnist Brian Hibbs called The Walking Dead “without a shadow of a doubt, the biggest success story” of the year, pointing out that the books collectively hauled in a mind-blowing $8.7 million dollars.

But back to that $10,000 first issue, which the seller called "an investment as The Walking Dead is now a permanent part of our pop culture and continues to grow in popularity." While post-1990s, most of us scoff at the idea of comics as investments, The Hollywood Reporter notes in this instance it may hold true: A 9.9-rated copy of The Walking Dead #1 sold for $7,000 in March, while a year earlier an identically graded copy was purchased for just -- "just"! -- $2,500.