As Seen on TV - Auto Fan Solar Powered Air Ventilation Pet/Tobacco Odors Eliminate - Black Plastic

Users of this fan need to remember that to blow air out of the car you need an entry point for the air to enter. Most recent cars have one way vents so that they exhaust when the car heater/air conditioner is on but block the air when the the hvac is off. I put the fan on one of the sunward side windows and crack the diagonal window on the shady side to let air in, and use a sun shade in the windshield. The fan results in a decent amount of additional cooling over that of the sunshade alone. Of course you have to watch out for rain that would enter the car with the window cracked.

Not worth the money. Unless it's in direct sunlight it won't work and even then it doesn't create enough air circulation to feel.