This article shows the results of the households' income and expenditures analysis. Special attention was given to the relation between food and alcohol-free beverages in general expenditures and social-demographic characteristics. Three criteria of households' division were introduced. The households were divided according to the main source of maintenance, according to number of members in the household, according to the economic situation. As a result of these steps we got 18 households subsets. For each subset the linear econometric models were estimated and verified. These models illustrate the Engel's Law. In the next step of analysis the classification rules were generated with use of data mining techniques. Data mining analysis was made for the same subsets as previously econometric models. As an output we got the rules with economic interpretation, allowing for complement of households' characteristics resulting from research based on econometric techniques.