A Game of Thrones (like) Party - costume suggestions

Omega Castle

I am thinking of hosting a Game of Thrones (like) party in the cold weather and would really appreciate some help from all the fashion DIY gurus out there.
I don't want to buy or hire comerical costumes, rather I would like to recycle/upcycle materials to have an original twist on the day.
So am looking for hints and ideas for everything from the leggings, cape, tunic, arm guards, accessories, hair etc etc
and best yet if the ideas are for things that are low cost or free - lets see if anyone can rise to the challenge
Thanks