Ebay but either way you will probably be spending atleast a hundred dollars for a whole set.
Ebay, Craigslist, other forums. I see them go for 20 bucks all the way up to 500 bucks.
If you are lucky you can find them at scrap yards. I was only missing the reverse lights.
Looking for a Used Fairmont in your area?
CarGurus has 1 nationwide Fairmont listings and the tools to find you a great deal.
Search Ford Fairmont Questions
Ford Fairmont Experts