This is cool, but the first three
Calvin & Hobbes treasuries, the ones collecting two collections each, are on sale at Amazon Kindle for $1.99
and marked as Comixology compliant.
http://www.amazon.com/Authoritative-.../dp/B00FWOKE2I
They aren't actually showing up on Comixology yet, but I'm sure that will be fixed shortly.
Also, fwiw, another freebie.
https://www.comixology.com/Boys-Over...l-comic/325771