Why do some listing not have market value

There are not listings or sale info to give a proper calculation. If you are looking at the F-250 you have multiple variations and conditions depending on year model. A 2001 F-250 reg cab gas burner with 100k miles may bring $4k while the same year F-250 in a crew cab 4x4 Diesel with 100k miles may bring $20k. Research all the sites for pricing info they may not have an analysis but you can still gauge value by what the average asking price is on similar vehicles and you can still use a model year older and newer to help with the comparison unless you are looking at something that had a change for the model year.