usps priority small flat rate box price is a popular option for customers who need to send items quickly and affordably using the USPS. The USPS Priority Mail Small Flat Rate Box provides a fixed price for shipping, regardless of the weight or destination (within the United States). This option is ideal for sending small, heavy items or items that need fast delivery. The price for the Small Flat Rate Box varies, and customers can check the USPS website for current rates and any applicable discounts or promotions.