Best cars in $15k-$20k range?

I'm going to be buying a new vehicle after I graduate college this summer. This price range is perfect for me buy a brand new car in that range is basic. I want a few luxuries in a car such as leather and nicer rims. For example a Chevy Mailbu LTZ or ford fusion titanium. Also, something that has pretty good gas mileage as well.

My car makes a whirring noise, what could it be?

When idling, my 4 cylinder Ford Fusion makes a whirring sound, almost like my car is electronic. Just kind've a weird higher pitched sound that doesn't sound like a gas engine. Its always made this noise (since I bought it), and it's been fine to drive for a year. What could it be?