How much did you pay with shipping? If you go to Flex-A-Form.com and look at their fiberglass leaf spring that cost about $400.00 a pair with poly bushing and weigh only 8lbs. each you may find that they don't cost THAT much more than steel springs.
Cheapest: If you have the old ones, find a spring shop in your area and have them rebuilt which would include re-arching and probably heat treating and should be be able to get the busings etc from them.
next best, but very good: contact Eaton Spring, they can make up anything pretty much for you
if you can find springs for a 67 fairlane, they will interchange with the 67 falcon. also check with autokrafters as they will get springs for you for about $250.