Water bottle or bottles, at least 32oz capacity, a survival *swiss army* knife, a whistle, some sort of a mini flashlight (make sure your battery will work for this) and a first aid kit (band aids- alcohol prep pads) tucked away in a zippered pouch. Don't forget a rain poncho. Just a cheap one will do to help keep you dry. Get a few of them just in case you have a few passengers with you. Then you can find the Mylar Emergency Blankets at just about any Dollar Store now days. Get a few of them just in case you travel with a few people in your vehicle often.
Don't forget that all important compass, so you know what direction you need to go in.
Even a Dollar Store set of binoculars will help you out with having to take all those extra steps in the wrong direction. Or to help find water or shelter, so you don't have to walk so far.
You can put all this together for around $10-$15 or even less. It's worth it to just tuck away in your vehicle and be safe in case you may ever need it.
2) survival *swiss army* knife
4) mini flashlight-plus batteries
5) first aid kit (band aids- alcohol prep pads)
6) rain pouch
7) Mylar emergency blankets