The Microsoft store currently has the Ultimate Edition priced at $99.99 and it comes with a $10 promo code. It's the same price as the US version and it's not marked as a discount so it's probably an error since it's $130 everywhere else. It's a decent deal since you're basically getting all the Ultimate Edition junk for $10 if you were planning on buying Horizon 3 anyway.

However, it is the disc version so won't come with the Windows version.

And they've fixed it.

It's weird how this keeps happening. They had the Destiny expansion on the PSN store at the wrong price for a day or so as well.