Crusader Kings II and some DLC for the game are sale for 75% off at GMG. Stacks with their 25% off voucher code GMG25-UAAHK-6AI9S.
Looks like GMG sells the Steamworks, version of CKII, so all of the titles below require Steam activation. Prices listed are before the voucher code.
Crusader Kings II: Legacy of Rome = $1.24
Crusader Kings II: Ruler Designer DLC = $1.24
Crusader Kings II: Songs of Albion DLC = $0.49
Crusader Kings II: Songs of Faith DLC = $0.49
Crusader Kings II: Songs of the Holy Land DLC = $0.49
Crusader Kings II: Songs of the Caliph = $0.49
Crusader Kings II: African Portraits = $0.49
Crusader Kings II: African Unit Pack = $0.49
Crusader Kings II: Sword of Islam = $2.49
Crusader Kings II – Dynasty Shields DLC = $0.49
Crusader Kings II = $9.99
Crusader Kings II – Mongol Faces DLC = $0.49
Crusader Kings II: Byzantine Unit Pack = $0.49
Crusader Kings II: Songs of Byzantium = $0.49
Click here to see the Crusader Kings II titles on sale at GMG.