cheapest way to ship a large box depends on various factors, including the size, weight, and destination of the package. One of the most cost-effective options for shipping large boxes is USPS Ground, which offers affordable rates for heavier packages. For faster delivery, services like UPS Ground or FedEx Ground may offer competitive rates, though these typically depend on the specific shipping requirements. Comparing prices across different carriers and using tools like shipping calculators can help determine the cheapest option for shipping large boxes.