Well, its kind of like, how much is a 1" combo wrench. Its all about new, vs used, vs brand, vs premium, vs economy. With chains, there is the grade factor, which the vast majority of sellers don't know or care about. Rusty used ones seems to go for $40 to $80 for a 20 ft section. I only haul my vintage tractors, and an occasional vehicle on a gooseneck. Since I am not DOT controlled, I dont have to worry about inspections.
If buying used, inspect every link.