I made an Air Dam from a Lund Bug Shield that I found at the local Salvation Army Thrift Store. It was new in the box and was made for 1999-2003 Ford F-250, F-350 Pickups, and 2000-2003 Ford Excursions. I bought an 8 foot strip of commercial Corner Guard to use as a bracket and some stainless nuts, washers, and screws at Home Depot. After it was installed, I cut off the excess bug shield that extended outside the width of the bumper with a Dremel and small cut-off wheel. It is very low and I have "nerfed" the ground a couple times already. I wanted to have a more professional look about the Air Dam than the average lawn edging mod and believe I met that goal.
