There are a myriad of places to purchase an underground steel shelter, including Steel Storm Shelters, Ultimate Bunker, Cozy Cavern Storm Shelters, Rising S Company and Guardian Storm Shelters. Since everyone has different needs and preferences, nearly all orders are custom jobs.
These companies tend to cluster in states known to have severe weather events, such as Arkansas, Virginia, Kentucky, Tennessee and North Carolina. It is also a niche market, so it is generally necessary to call ahead for an appointment to speak to a live person. All of the above companies offer some sort of online catalogue and can ship their products to customers.