united states postal service rates for priority mail are the costs associated with sending packages and letters via USPS’s Priority Mail service. Priority Mail is a faster and more reliable service compared to regular mail, offering delivery within 1 to 3 business days, depending on the destination. Rates for Priority Mail are based on factors such as the weight, size, and destination of the package. USPS also offers flat-rate options for Priority Mail, where customers pay a fixed price regardless of weight or distance, as long as the package fits within the designated box size. Priority Mail includes tracking and free insurance up to $50.