The clock is ticking down at Humble Bundle on Skybound's The Walking Dead Bundle, which allows customers to name their own price for DRM-free digital editions of the first volumes of Ghosted, Invincible, Witch Doctor and, of course, The Walking Dead.

The deal doesn't stop there, however: Those who pay more than the average amount offered ($11.59) can unlock the second and third volumes of The Walking Dead, the first volumes of Thief of Thieves, Manifest Destiny and Clone, the first and second volumes of Super Dinosaur, and the second volume of Invincible. Fifteen dollars will also open the fourth and fifth volumes of The Walking Dead.

But wait -- there's more! For $40 or more, customers unlock The Walking Dead, Vol. 20, and an exclusive T-shirt; $65 or more gets everything, plus a limited-edition Negan action figure. All of that's on top of the free first three issues of The Walking Dead.

A portion of proceeds goes to support the charities Penny Harvest, the Rett Syndrome Research Trust and the Indie Cade Foundation. The promotion ends in just a few hours.