The paper deals with the issue of price discrimination in the theory of economics. Although price discrimination is a heterogenous notion, Mokrogulski says, its different types can be presented in an integrated model with respect to the quantity and quality of a product as well as commodity bundling. Price discrimination is not the same as price differentiation, the author says. In particular, price discrimination does not occur when the differences in prices fully reflect the differences in production costs. If the seller is unable to make a consumer buy a specific version of the offered product, then a self-selection mechanism is applied. The goods and their prices are differentiated in such a manner that consumers choose versions somewhat pre-planned for them. In the empirical part of the paper, Mokrogulski checks a hypothesis about the existence of price discrimination on the Polish market for new automobiles. Cars are increasingly offered as a package transaction that includes transport services and various extras such as air-conditioning and electric windows. As it is impossible to separate the two parts of the package, Mokrogulski says, price arbitrage cannot be applied, while demand arbitrage is possible. To check if price discrimination indeed took place, differences between the listed prices of two versions of the same car model were calculated. Then they were compared with the differences in the actual prices. “The results predominately confirm that car dealers use a further segmentation of customers, who usually have to pay for certain luxury extras,” Mokrogulski writes. Further empirical research is needed, the author concludes, to analyze the problem of price discrimination in other markets with a different level of competition and a different stage of development.