The Steam autumn sale is currently going on, and the Civ titles are getting some discounts:
- #Civ7 is 30% off, for 48.99 (base game) https://store.steampowered.com/app/1295660/Sid_Meiers_Civilization_VII/
- Most, but not all, DLCs get between 20-33% off, which includes Crossroads and Right To Rule (the later 20%) https://store.steampowered.com/dlc/1295660/Sid_Meiers_Civilization_VII/

For other Civ titles https://store.steampowered.com/franchise/civilization?snr=1_5_9__2001 , we have:
- #Civ6, 90% off for 5.99
- Beyond Earth, 75% off, for 9.99
- #Civ5, 75% off, for 7.49
- #Civ4, 80% off, for 3.99
- Alpha Centauri #AC , 50% off, 2.49 https://store.steampowered.com/app/2204130/Sid_Meiers_Alpha_Centauri_Planetary_Pack/

Currently there are no discounts for Civ3.

And some more interesting news: Some forum sleuths found some good indicators for some future content, please check here https://forums.civfanatics.com/threads/asset-file-hinting-at-future-and-or-cut-content.695000/page-45#post-16872550 .