To decide on interventions in a market economy politicians have to consider the temporary and intertemporal coordination achievements of market behaviour, as reflected in static and dynamic economies respectively. In this respect the barrier market concept might serve for guidance. The barrier market amounts to a formal elaboration of the workable competition concept. In this paper a model is presented of decision making of an individual supplier in a barrier market. Moreover, results are offered of analyses of competitive processes in which heterogeneous suppliers interact over time.