The income of trade organizations and the level of retail prices to a significant extent depend on the effectiveness of trade transactions in purchasing of goods. In the conditions of competitive environment, even non-significant decrease of prices leads to the increase of the loyalty of buyers and to the increase of the volume of sales.The article presents a method for assessing the effectiveness of commercial transactions, the use of which allows to increase income and profit of a trade organization and the competitiveness thereof on the consumer market.