What is the cheapest shipping method depends on the size, weight, and destination of the package. For small and light items, USPS First-Class Mail is typically the most affordable shipping method. For heavier items, options like USPS Priority Mail or flat-rate shipping might offer better rates. International shipping costs vary, and sometimes services like ePacket or international postal options can be cost-effective for certain regions. To determine the cheapest shipping method for your needs, it’s best to use online rate calculators from carriers like USPS, FedEx, UPS, and DHL, which allow you to compare rates based on specific parameters such as size, weight, and delivery speed.