The first issue of the Batman/Fortnite crossover, Batman/Fortnite: Zero Point, has become a surprise force on the secondary market, as first print copies of the first issue have sold on eBay for over $100.
One of the main selling points of the series is that each issue (which ships in a sealed polybag) comes with a redeemable code for special digital items that are based on the story of the comic. The first issue, for instance, has a new Rebirth Harley Quinn outfit that can be used in the game. If you collect the codes from all six issues, you are able to redeem them all for a special Armoed Batman Zero outfit for the video game.
One issue for retailers is that this comic book was not solicited through the normal process, but was added at "final order cutoff" time. Comic book retailers, you see, make initial orders at one point and then have to make their "final orders" roughly three weeks before the comic book is released. Here, Batman/Fortnite: Zero Point #1 (which was done by Christos Cage, Reilly Brown, Nelson DeCastro and John Kalisz, with a story concept by Epic Games' Donald Mustard) was not available for initial order, only final order cutoff (although DC did then delay the final order date, giving retailers a second week to make adjustments before locking in orders). This gave retailers less time to gauge interest in the product from their customers.
The bigger issue, though, is that the comic received a major publicity boost from Epic Games, the maker of the Fortnite game upon the release of the comic on Tuesday, featuring the comic on its home screen and tweeting out to its social media followers about the code. By that point, though, comic book retailers had already had to place orders for the first four issues of the series (Lunar Distributors, DC's distribution partner, did then extend the order time for #4 to Wednesday).
As a result, a comic book that was selling for cover price on eBay last weekend was then regularly selling for over $30 on its release date, with copies getting as high as $117, but settling into around the $30 range (especially after DC announced that there would second and third printings for all of the issues of the series, and the later printings would have the same redemption codes as the original printings).
Expect similar responses for #2 and #3, as both of those issues were ordered in even lower amounts than #1.