Well the base Battlestar Galactica Deadlock is only 15 bucks on GOG this weekendby Mischief Maker 06/29/2019, 6:21am PDT
The bad news is it kinda needs its DLCs.
"Reinforcement Pack" is the only one I would say is absolutely mandatory. The Berserk assault carrier is downright essential in the earlygame and still useful in the late game: