How do components of revenues and expenses differ between a merchandising company and a service company?

In your own words, define materiality. Provide an example to support your conclusion.

Nida Hat Shop received a shipment of hats for which it paid the wholesaler $2,940. The price of the hats was $3,000, but Nida was given a $60 cash discount and required to pay freight charges of $75. What amount should Nida include in inventory? Why?

Marshall Company discovers in 2014 that its ending inventory at December 31, 2013 was $5,000 understated. What effect will this error have on (a) 2013 net income, (b) 2014 net income, and (c) the combined net income for the 2 years?