A common cause of increases in prices are increases in costs. For instance, demands by unions for higher wages have been labeled as wage push inflation. At other times, increases in commodity prices were attributable for inflation, for instance, in the case of the oil crisis of the 1970's.
The oil crisis of 1979-1980 caused oil prices to jump drastically in the early 1980's. The increased energy costs were passed on to consumers in the form of higher prices. In great part, that inflationary period was of cost push inflation nature.