I talked already about the first Europa Universalis IV expansion called Conquest of Paradise some time ago when I heard the Paradox Interactive announcing.
But now Conquest of Paradise is also available for pre-order and it seems that the price is around $15 which seems to be a very fair price for an expansion in my opinion. If you already own Europa Universalis IV, then you might be interested to pre-order the expansion Conquest of Paradise.
I think there are a few stores where you can do that but the biggest that come to mind are Steam and GamersGate. I found out that you can pre-order the expansion on both platforms. It will be a digital download. I guess I do not have to mention that you need the main game before you get the expansion on the release date January 14 this year 2014.