Humble Bundle is offering the digital editions of The Walking Dead comic volumes for the next two weeks. You get Volume 1 (Issues 1-6) along with the first five issues of "Invincible", "Witch Doctor", and "Ghosted" for the minimum amount. For $10+ you get WD Volume 2&3 (Issues 7-18) and the first 6-7 issues of "Thief of Thieves" and "Super Dinosaur". For $15+ you get Volumes 4&5 (Issues 19-30) of Walking Dead.
https://www.humblebundle.com/thewalkingdead