I know it's killing you right now to not have your own car, but this advice is probably going to add salt to the wounds. The advice is simple: never be without a AAA membership. Ever. AAA is the American Automobile Association and they can save your bacon if you find yourself with a disabled car on your hands.  

As a AAA member you can avail yourself of their roadside assistance program. Notice that I linked to their plus service, which is worth every penny. 

Here is why you need it:

1. Saves you money: Even if you only use the tow service once a year, you've saved money. You don't have to worry about the tow shop ripping you off nor do you need to worry about someone showing up. Additionally, when you lock the keys in the trunk again, and no one can come and help, AAA will send someone out to open your car. Don't even start me on frigid, arctic like winters when your car won't start. 
2. Saves your dignity:  You are going to own some real pieces of junk in your lifetime. You can save yourself some dignity by ensuring AAA is there to help when the junker eventually falls apart. Oh, and it's not if it falls apart, it's when.
3. Saves you time: By happenstance let's say your car makes it to work, but when you go out to lunch it won't start. All you have to do is go back to your work, call AAA and get on with your day. You don't have to look up tow companies, you don't have to call service stations. One call and your back to your life. 

Your mother and I have seemingly had a 20 year disagreement about AAA, but when our car broke down between here and St. Louis the arguments ceased to exist.