The concepts of supply and demand and related terms are taught through stories about the toy fads of Hula Hoops and Silly Bandz. In 1958, Wham-O, Inc. began marketing the Hula Hoop in the United States and sales of the Hula Hoops sky-rocketed as over 25 million were sold in the first few months, within the year over 100 million. Similarly today, Silly Bandz has taken off in sales since the summer of 2008.