The Grudge Keeper says when he enters play, he can put a support card into play from his hand to the battlefield. Does this mean the support card is put into play without paying the resource cost ? I know that in Star Wars LCG " Put in play " cards do not cost resource points to play. Is this true for WI ?

Yes.

Thanks !

Thought about ànother put into play question.

Dwarfs have some different vengeance card like

Blood vengeance

http://deckbox.org/whi/Blood%20Vengeance

Stone vengeance

http://deckbox.org/whi/Stone%20Vengeance

Is this also à card you may play without paying the cost and loyalty cost?

Yes, you can put it into play for free when your capital is dealt damage or you can play it normal from your hand (paying cost and loyalty)