Show how they can be used to reveal how a market clears. Using diagrams, show also what might happen to prices and quantities for a normal good if, over several periods of time, there are steady increases in income per head and in technical progress: Where there is demand there is a supplier and sometimes suppliers can create demand. There are many factors that influence demand for goods and services in the market place; some are the result of natural demand born of basic necessity or perceived needs, and however firms can create desire for a product through the study and manipulation of the forces in demand and supply. Every firm which provides goods or services to fee paying customers must, by its very nature, charge a price for that good or service, to pay for its costs, have retained profits for investments and to keep its shareholders happy