If you're hearing a squealing or squeaking sound coming from the front
of your Ford Fusion while braking, you probably need to replace the
front brake pads. They tend to last anywhere from 40,000 to about
60,000 miles depending on your driving style.
Here's the guide -
http://www.paulstravelpictures.com/Ford-Fusion-Front-Brake-Pads-Replacement-Guide/index.html
A set of new brake pads range in price from about $25 for the economy
semi-metallic pads to over $65 for better ceramic pads. I've had good
luck with the Wearever brand of ceramic pads at Advance Auto Parts for
about $40-$45.
Cheers,
Paul