The 1978 BSG series was supposed to have "incredible" special effects. In fact, very few of the effects were special at all. Expensive, yes. This was, after all, a television series rather than a motion picture. BSG spent about $750,000 an episode (about a third of this cost being charged to Universal rather than ABC; note, this is NOT the oft-cited "$1 million an episode" claim), of which about a third went to salaries.
Sets -- and filming the sets -- were the most expensive production cost. The Galactica bridge cost $850,000 to construct and included $3 million worth of computer keyboards, monitors, and reel-to-reel tape decks donated by Tektronix. The large bridge set was designed in sections that could come apart to allow filming, but this was time-consuming and expensive because it required unhooking all the electronic equipment and then reattaching all the cables and power again.
To cut back on effects costs, BSG re-used effects shots over and over and over. Numerous "beauty passes" of ships were made. These were then used to with matte shots of explosions or planets to create a wider variety of effects.
Nonetheless, most of the effects were cheesy. In this shot, a Cylon Base Star explodes. Notice how the sparks float downward? Gravity. Notice how the "explosion" is mostly sparkles and flame? Typical effects explosion.