The National Motor Freight Traffic Association (NMFTA) annually publishes a list of freight class designations, codes, and subclasses for commonly shipped items (https://classit.nmfta.org/). To access this list, you are required to pay a subscription fee. Learn more about freight classes for free on our freight classes pages.
Freight class 50 is the least expensive because it refers to the freight that is easiest to transport for the carriers.
NMFC freight classes are determined using four factors: density, handling, stowability, and liability. All of these factors affect the cost to the carrier of shipping goods.