Marxist economics
Marx viewed the capitalist class (the bourgeoisie), those who control the means of production, as leech-like and unnecessary; they are not necessary for the production of the goods society must consume in order to meet human needs and reproduce itself. Rather, Marx saw the capitalist class as getting wealth for itself by the exploitation of the working class. Marx argued that wages under capitalism are determined not by the value created by workers during a given period of time, but by the cost of their labor power (ability to work). He argued that the cost of labor power is determined by the cost of the goods and services (food, clothing, shelter, child care, education etc.) nececssary to maintain and reproduce workers. So, capitalists do not pay workers for the value they create: they extract Surplus value, the difference between the value created by a worker and the cost of their labor power (their wages), from the working class. In other words, surplus value is unpaid labor performed by the working class for the capitalist class, which Marx termed exploitation.