Just in time for the release of the new movie Thor: Ragnarok! Amazon are offering a number of Thor Graphic Novel eBooks for free! Get 1, 2 or all 3 - totally for free!
Titles include:
 - Thor: God of Thunder Vol 1: The God Butcher
 - Thor by J. Michael Straczynski Vol 1
 - Thor Visionaries: Walter Simonson Vol 3 (no longer available)
Limited time only!