Not only that: GOG sells the old base game which does not include Crusade nor any of the DLCs included in the current core game package offered at Stardock and Steam! GOG currently sells the original base game at 30$ and Crusade at 19$, which brings the total price up to 49$. Of the DLCs that are included in the core game package, GOG sells one at about 3-4$, the other one or two DLCs are available for free. This brings the total price at GOG at over 50$. What's more, while GOG did offer the game at discount occasionally, I've never seen any of the expansions or DLCs on discount over the past year.
P.S.: Sorry, wrong forum - I was talking about Galactic Civilizations 3 - didn't notice I slipped into a different forum.