Abstract: For a class of continuous time incomplete financial markets （in which the price processes of securities are driven by Brownian motions） E1 Karoui and Quenez 1 developed the theory of pricing contingent claims. Making use the decomposition theorem established by Follmer and abanov 2, we indicate in this note that the basic results and methods in 1 about selling and purchase price processes are also suitable for general finite discrete time financial markets. Inparticular, we give another reasonable interpretation for selling and purchase price.