Buying a car? Advice?!?

So, I'm ill be 20 in August, currently in my second semester of my 2nd year of college. I currently do not have a job but really need one. One major issue with this is lack of transportation. I need a car!! Unfortunately I'm not one of those lucky people who's parents buys them a car at 16... It's so hard to get around, go to school, practice, errands, and now a job without a car... How much money do you think would I need to save up to buy a decent car? Nothing fancy, just something reliable with decent mpg. I'm trying to get my parents to help loan me the money now and then pay it back to them little by little every month but they don't exactly have the money either. Advice?? Thanks