In business transactions, it is quite common for the supplier to offer the retailer a permissible delay in payments in order to stimulate the demand of the retailer. The retailer can either pay off all accounts at the end of the credit period or delay incurring interest charges on the unpaid and overdue balance due to the difference between interest earned and interest charged. In this study, we consider different financial environments when the supplier provides a permissible delay in payments. The proper mathematical models are developed to find the optimal order quantity and payoff time for maximizing the retailer’s total profit for each financial environment. Furthermore, two theorems are established to determine the optimal solutions. Finally, numerical examples are presented to illustrate the proposed model. A sensitivity analysis is performed and economic interpretations are proposed.