Oh, you too are another victim of "the Pelican."
I've had it with Pelican video products. I've been through 4 sets of Pelican GC/N64 S-video cables (cuz I usually have 2 sets at a time, one for the main TV, one for my PC for video editing). I tossed the first 3 for reasons like the S-Video sending only black and white images, or the audio cables quit sending sound altogether, after a period of a few months. The latest one I tried was defective out of the box, where the S-video picture had an organized mess of dots all over the screen, and looked much worse than the composite video's "dot crawl".
I'll agree that Monster's cable is the best set out there, but yeah $30 is almost rediculous. The next best thing you should look for is Mad Catz' S-Video cable for GameCube. I'd say it's well-constructed since each of its 4 cables is shielded throughout the whole length of the cable, unlike just about every other ~$10 GameCube S-video cables I've looked at, including Pelican's, and even Mad Catz' own Universal S-Video cable. Also, it seems it's twisted-wire design helps block more noise/interference, cuz all the audio/music I've recorded from some of my games (like 1080, for ex.) came out noticeably clearer than that of any previous cable I've used. S-video picture is excellent, tho I suppose Monster's provides the best image possible.
Here's how they look. The bulk of the cable is the 4 main wires twisted and wrapped in a see-thru sleeve.
http://www.ebgames.com/ebx/product/224949.aspI got mine for $8.99 at an EB store in my town.