So here's something i wanted to share.
I own an Xbox One but I decided I'm selling it with my Digital games included. The reason I bought it is for KI and that's coming to PC like the other MS Studio developments (Recore etc). I'll get to the point. I opened up a new Xbox live account and grabbed Killer Instinct Ultra Edition for Free last night! At first I thought it wouldn't work because the MS Store sucks and it wouldn't let me claim the games for gold. I searched and forums said that 15 day trials don't let you have Games for Gold. But I was on a month trial that you get when you sign up new. So I googled "Killer Instinct Season 1 Ultra MS Store" and google linked me to a page that said $39.99 - Free. So I hit the Free button and it gave it to me! Naturally I bought the Shadow Jago Exclusive character too because, Heads Up, you have until tonight to buy him, tomorrow #REALBOY will no longer be available! So that's my story. Made a new xbox live account and got a free PC game.. a game so good that Amazon bought the developer. Yess it's a really good game.
TL;DR
Sign up for a Microsoft account on your PC
Sign up for Xbox Live and choose 1 month free
Google "Killer Instinct Season 1 Ultra MS Store"
Select "Free"
*Bonus* Search Shadow Jago and buy his character before time runs out (1/15/16)
You'll have a free PC game come March..
How to Get Xbox Live | Xbox Live Gold Trial Membership
*Update* Been informed that Games with Gold for X1 is good while you maintain or renew a live membership a la PS+.