So here's my list of essential tools to keep in your car. I'm not getting compensated in any way for listing these products. I figure if I include links (free advertising) they won't mind me using the images. I selected products that I'd likely buy if I needed a new one.
Flashlight
It gets dark. 'Nuff said. Get one. Keep it in your glove box.
Electric air pump
An air pump is one of the most needed tools to keep in your car. Usually when I stop to help someone change a flat tire, their spare tire is under-inflated. So I go get my air pump and fill it up.
Tow strap
You can pull off the road and get stuck in the mud. You can slide off the road in a snow storm. Your car may not start. Whether you need to call a friend or be a friend, a good tow strap is handy.Jumper cables
Lights get left on. Batteries get old and die. Alternators fail. A good set of these jumper cables can help you on your way. Two things to look for are gauge and length. A 25 foot long set of 1 gauge cables will allow you to park behind a car and jump start it. Have you ever needed to jump start a car on the side of the freeway?Breaker bar
Sometimes you need more leverage than you can get with a typical lug wrench. Sometimes those lug nuts are on so tight, expletives slip out. A good length breaker bar may do the trick. But don't forget the set of metric deep sockets. I like this set that has no missing sizes between 10 and 24 mm.
Jack
Unless you have a set of run-flat tires, you probably already have a jack in your car. Just make sure it's not broken and works for your car.Set of metric box wrenches
Did your serpentine belt break while driving? Do you need to clean off a battery terminal because your car won't start? I like this set with no missing sizes. Did I mention my pet peeve about missing sizes?
I once stopped to try and help a guy that was trying to install a serpentine belt without any tools. I didn't have any wrenches on me at the time, but sure could have used a set like this.
A couple weeks ago, I stopped to help a guy who had a battery terminal corroded, but I had left my box wrenches at home. Oops.
So, how much does all this cost? Not including the jack (which you should already have), it's about $222. There are other tools that may come in handy, such as a screwdriver, or even as simple as a pen. But these are the tools that I find are most needed. Is it worth it? If having the tool is the difference between fixing it yourself or calling a tow truck, then yes I think so.