You can get replacement wiper blades for the Ford Five Hundred at many pleaces. However, when buying windshield wiper blades be sure to always look up your vehicle make, model and year in the application guide book at the store, or now-a-days you can Google 'lookup wiper size'. You want to look this up because correct wiper fit is more than correct length, it's also proper attachment. Not all attachments fit all arms. Using the application guide or looking up wiper size online will avoid the headaches of buying the right lengths with the wrong attachments.
A note on installation: The replacement wiper blades will come with simple-to-follow, step-by-step, illustrated instructions and once you have the instructions and the wiper blade/arms in your hands and in front of you, it will all make sense and will an easy maintenance task. The old ones simply snap-off and the new ones simply snap right back on. Very simple and takes 5-15 minutes usually not requiring any tools.
If in your budget, upgrade to the newer-style frameless "beam blades" which perform better than conventional framed wipers. I use 'Trico Tech Beam Blades' which are fantastic and easy installing.
The 2005-2007 Ford Five Hundred takes 24" driver side and 20" passenger side replacement windshield wiper blades.
The 1998 Ford Ranger takes 18" replacement windshield wiper blades on both sides front.
The 2005 Ford Explorer takes 20" replacement wiper blades on both sides front and a 16" rear.
It's a 20 in. wiper blade
The 1991-2002 Ford Escort takes 20" drivers side and 18" passenger side replacement windshield wiper blades on the front and if applicable, a 14" rear wiper blade.
The 2002 Ford Windstar takes 24" driver side, 20" passenger side and 16" rear replacement windshield wiper blades.
The 1997 Ford F-Series Pickup takes 22" replacement wiper blades on both sides front.
The 1994-1997 Ford Aspire take 20" driver side and 16" passenger side replacement windshield wiper blades.
The 1996 Ford Windstar takes 24" drivers side, 20" passenger side and 16" rear replacement windshield wiper blades.
The 2009-2010 Ford F-Series Pickup takes 22" replacement wiper blades on both sides front.
The 1999-2008 Ford F-Series Pickup takes 20" replacement wiper blades on both sides front.
The 1980-1996 Ford F-Series Pickup takes 18" replacement wiper blades on both sides front.