This paper investigates the behaviors and the properties of a "Give and Take" cellular automaton on a graph. Using an economical metaphor, this model implements the exchange of cash against goods, among the nodes of a graph G, with a local pricing mechanism. During the time evolution of this model, the strongly connected components (SCC) emerge, mimicking the creation of independent sub-markets. In the steady state, each SCC is characterized by a unique price obeying the supply and demand law for that sub-market. We also show that the distributions of cash and goods are proportional to the indegree of the cells, reproducing a Zipf's law of wealth distribution in case of a scalefree graph topology.