miller57,
I amdthe inventor an own the LeverLift Company that makes the lift kits for the Sport Trac OEM tonneau covers.
The price for used tonneau lift kit would very based on which model you have. The early versions used a see-saw lever mounted to the side of the pickup bed, with gas springs attached to each end of the lever. While they worked fine, they were subject to wear at the pivot point and occasionally would bend the aluminum lever. These units are at least 4 iyears old and probably have very little value.
The latest model (the EZLift) is a redesign that eliminates the levers and the problems associated with mechanical failure. The new kit sells for $120 plus shipping and comes with a 1 year warranty on parts and 3 year warranty on the gas springs.
I suspect the value of the older lever-action kits would not be more than about $20, and that would probably be for parts only. Replacement gas springs are $32 per pair plus shipping, and I don't make any of the lever parts anymore.
...Rich Lunder
The LeverLift Company