The purpose of this final work is to explain the term consumer's surplus and how it is measured, and to get to it we had to find out who the consumers are, which are their assumptions and how the consumers meet their desires and needs by buying certain products and services. It has been attempted to search out how price changes affect consumers and their surplus. The results of the research have shown that consumers are price-sensitive and that price reduction affects them positively because they buy more at lower prices, but affects positively also the consumer's surplus because prior to the discount a certain consumer was willing to pay the full amount for a particular product and he pays it less, so his surplus grows. The consumer's surplus is measured by the difference between the price consumers are ready to allocate for a product and the price they really pay for it. We also tried to explain the pricing strategies that are the means to gain the consumer's surplus and his conversion into additional profit, and this can be achieved through price discrimination. Apart from the influence of prices, consumers are also subject to tax effects. Tax disrupts market activity and its introduction reduces the total surplus and the deadweight loss.