Saites2001 writes “Recently I saw a commercial for a car vent that ran on solar power. It seemed like a good idea, but outrageously overpriced. The one on TV was $15 + S&H. Online they run as high as $40. I decided I could build one that was more functional and for under $10. The outcome is not exactly a looker, but it works and only cost $6.” – Link.
$6 Solar fan