Marxists approach economics from a particular perspective. We have to accept that wealth is concentrated in the hands of a very small number of people, the capitalist class. The overwhelming majority of people have no wealth. All in essence they have is themselves and their ability to work, which they have to sell on the open market. Marx called these people the proletariat. Steve Jones, of the Socialist Appeal editorial board, talks on the basics of Marxists economics.
Part 1
Part 2