Ah, Luigi Cozzi's Starcrash. First in a projected series of films about the shapely space adventuress Stella Star that, sadly, never got off the ground.
Saw this in a Texas drive-in in a double feature with Laserblast when I was six. To this day, it's still a personal favorite. Cheap, yes, but actually much truer to the '30s pulp tradition than Lucas' bloated space opera. And it has Christopher Plummer in one of his most memorable roles:
Yes, that is the Hoff. And it also has Marjoe Gortner as a mutant armed with a damn lightsaber. And of course, the lovely Caroline Munro as Stella herself. This is some serious-ass star power here, folks. They weren't kidding around.
Funniest thing is that John Barry did the score under the preconception that it was a big-budget affair and not a cheap Italian B-movie. Years later, he recycled the main theme for Out of Africa and won a Best Score Academy Award for it.
Technically that's against the rules — that was how Jonny Greenwood was disqualified from an Oscar nomination for his There Will Be Blood score — but I guess none of the Academy voters had heard of Starcrash. Their loss.