Next time your car battery dies, instead of calling friends or a tow truck, call an Uber and have them run the meter while they give you a jump. It will cost you around $8 instead of the $50-$75 a tow truck will cost (caveat: you most likely will need your own jumper cables).
http://www.amazon.com/Stanley-J5C09-500-Amp-Built-In-Compres...
You'll never be stranded with a dead battery again, can inflate flat tires wherever you are, and can charge your cell phone if your battery can't be revived. I bought one years ago after dealing with a bad alternator and keep it in the trunk of my car; so much peace of mind. You even get to be a hero, jumping other peoples' stranded cars without needing cables or risking your own car.
Check the battery fluid level. If its low, you may use some bottled water to fill it up. Chances are the car will startup and allow you to get home. Note that you should replace the battery after doing this.