GamersGate.com has a weekend sale featuring Galactic Civilizations games and DLC.
GalCiv III - 50% off
Reg. $49.99 Now $25 - Get it now
Revenge of the Snathi DLC - 50% off
Reg. $4.99 Now $2.50 - Get it now
Precursor Worlds DLC - 25% off
Reg. $4.99 Now $3.74 - Get it now
GalCiv II: Ultimate Edition - 66% off
Reg. $19.99 Now $6.78 - Get it now
And several more are on sale! View the full sale here.
Sale ends 1/25/16.