Used container pricing is driven mainly by local supply, and 40' shipping containers are a far more common size than 20' shipping containers. Because containers are a byproduct of shipping, the containers that move the most cargo tend to be the most widely used. So 40' shipping containers (standard and high cube) are the most common used container length and tend to be less expensive per square foot than 20' shipping containers. Depending on supply, sometimes used 40' shipping containers can even be the same price or lower in cost than 20' shipping containers (however, usually 20' shipping containers are a few hundred dollars cheaper than 40' shipping containers).