This study aimed to provide a mathematical model for the determination of optimal wind power price in the case of construction of new off-grid-connected wind power plants in different areas. The proposed model is based on nine features including construction cost, side costs (cost of replacement, maintenance, and repairs), pollution, electricity generation, profit, renewability level, green economy, rate of return on investment, and consumption. First, the inputs of the mathematical model were obtained by technical–economic feasibility evaluation of the study areas in the software Homer using the 10-year wind speed data (2006–2016). The optimal wind power prices were then determined in three different modes by solving the mathematical model with MATLAB. The modes considered in optimization were the construction of 1, 2, and 3 wind power plants in the study areas. Simulation of construction of wind power plants in each mode was conducted in the software Homer. The results showed that the optimal wind power price resulting from construction of 1, 2, and 3 are 0.159, 0.151, and 0.140 $ per kilowatt, respectively. The proposed mathematical model was found to have sufficient capability in determination of optimal wind power price.