priority mail charges Priority Mail charges are based on the package’s weight, dimensions, and delivery zone. USPS offers flat-rate boxes for one-price shipping regardless of weight or distance, making it a preferred choice for heavier items. Variable pricing is available for custom-sized parcels, and rates start around $9 and increase with size and distance. Priority Mail includes tracking and $100 of insurance, with typical delivery in 1 to 3 business days. Online discounts are often lower than retail counter rates.