I too was disappointed when I saw it was sold out and it more than doubled in price on eBay.
Thankfully I haven't bought it yet, on eBay they seem to be around $90-$100 which I'm just about OK with but that still excludes shipping to UK.
I was going to skip this as it is a US only promo but it would be so nice to own as I'm a big Killer Instinct fan. This game is so amazing on Xbox One and it's the main reason for getting it.
Feel free to add me if you fancy a few bouts.
Gamer tag: Mr Likey Serv
Also, would someone here please be able to help me get the KI pins? It'll be so helpful if you could. Many thanks.