According to classical economic  theory, the result of optimisation and market processes should be that every commodity, except for transport costs, is sold for one and the same price everywhere. But, in practice, price variation is observed on all markets. Nobel laureate, George Stigler has shown that this can be explained if the costs of seeking, and diffusing information about, goods and prices are incorporated in the model along with production and transport costs. So basic properties of the theory do not have to be questioned. It is all an issue of the presence of an assumption of "perfect information".  In collecting and disseminating information on prices and differences, we hope to bridge to a greater or lesser degree the knowledge gap.