There are some factors which can impact the demand and supply of the products and services and they are known as the determinants of the demand and supply. The first determinant of demand is the changes in the prices of the substitutes. Second factor is the change in the prices of the complements. Third factor is the change in the size of the general population or the target market. Fourth factor is the change in the interest rates and easy availability of credit. Demand is also impacted by advertising and changes in fashion. Moreover, seasonal changes, changes in technology and consumers expectations also impact the demand. On the other hand, determinants of supply include prices of the substitutes, complementary products, government policies and taxes, expansionary practices of the company and economic conditions.