The aim of this paper is, on the one hand, to provide empirical evidence about the existence and persistence of price dispersion, and on the other hand, to analyze whether the result meets Varian (1980) model, according to which, for the price dispersion persists in equilibrium, the position of each company in the distribution of prices (ranking) has to vary over time. The results confirm the existence of price dispersion, although the importance of it differs according to the type of product analyzed. Furthermore, evidence of the existence of temporal price dispersion is obtained as supermarkets change their position in the ranking of prices significantly after just three weeks. This certainly increases consumers search costs.

Key words: price dispersion, online market, supermarkets.
JEL Classification: D4, D83, L11, L66.