postage rate for small flat rate box is a fixed shipping rate provided by USPS for small flat-rate boxes, which allows businesses to ship items at a consistent price regardless of weight or destination (within the U.S.). The postage rate for small flat-rate boxes is typically more economical for lightweight items. This option is especially useful for e-commerce businesses looking to reduce shipping costs and offer affordable shipping options to customers. By working with fulfillment services like AMZFulfill, businesses can take advantage of discounted rates for small flat-rate boxes, making it easier to ship products at competitive prices.