The problem of price function determination for stochastic customer which maximizes revenue of service provider is considered. The game is that the customer wants to buy service at a low price and in the same time the company wants to behave in the opposite way. The probabilistic approach is used for the client behavior modeling. The quality criterion related to the expected company’s revenue for the fixed time period is introduced. Further, the equilibrium price is estimated using calculus of variations. The analytic solution has been obtained for the case where the customer arrival is modeled using exponential distribution for the dependence of arrival customer probability on time and uniform distribution for the dependence of selling probability on price. It is shown that the sufficient condition of maximum is fulfilled.