Is varying the price of goods sold to customers based on their persistence considered a form of deception?

The obligation is not to increase the price of the commodity beyond its market value. There is no harm in reducing the price for some customers. What is forbidden, however, is to increase the price for some customers to a value higher than the commodity's market value, especially if the buyer is unaware of the prices of goods or is naive. It is therefore not permissible to exploit their ignorance and charge them more than the known value.