Some great deals on GOG currently, many at their all-time lowest price (according to ITAD). I have not checked all 30 pages of the games on sale so you might find some more great deals if you care to look. Here are some I found:
Ori and the blind forest definitive edition: $10.09 (only 0.30 above its all-time low):
https://www.gog.com/game/ori_and_the_blind_forest_definitive…
Dungeon Keeper 2: $1.99: https://www.gog.com/game/dungeon_keeper_2
Dungeon Keeper Gold: $1.99: https://www.gog.com/game/dungeon_keeper
Syndicate Plus: $1.99: https://www.gog.com/game/syndicate
Might and Magic 9: $1.99: https://www.gog.com/game/might_and_magic_9
Total annihilation: Kingdoms+Iron Plague: $1.99: https://www.gog.com/game/total_annihilation_kingdoms
Total annihilation: Commander pack: $1.99: https://www.gog.com/game/total_anihilation_commander_pack
Imperialism 2: The age of exploration: $1.99: https://www.gog.com/game/imperialism_2_the_age_of_exploratio…
Alpha Centauri Planetary Pack: $1.19: https://www.gog.com/game/sid_meiers_alpha_centauri
Cossacks Anthology: $1.59: https://www.gog.com/game/cossacks_anthology
Enjoy.
Note that Dungeon Keeper 2 is buggy as all hell and crashes when trying to play multiplayer, even with all the recommended 'fixes' - shame, because DK was awesome when it worked.