Since it's Summer I'm sure you've experienced getting into your hot car, when it's been sitting out in the sun all day. Well there's a simple solution to this … Sunshades.
Sunshades are something I bet you've seen in lots of other peoples cars. I'm sure in a store you've considered getting one. Sunshades are worth the money during the brutal parts of Summer. They keep your car much cooler. I wouldn't say the claimed “44 degrees” on sunshades labels is accurate. It's definitely at least 10 degrees, probably more. That doesn't seem like a lot, but that's the difference between being unbearable in your car and warm. They help not only reflect sunlight out, but give the car shade.
If you want to buy one for your car they are available in all sorts of big-box stores, convenience stores. and auto parts stores. They sell for about $10. I wouldn't buy a Sunshade at those stores though! They are available at Dollar Stores, and usually sell for about $3.
Below are Sunshades we've had for years. They've lasted a long time, and work well. I personally prefer these Panel Sunshades, to those Fold-Up Accordion type. The Panels can fit easily under a seat.