post office priority mail prices vary depending on the weight, size, and destination of the package. USPS Priority Mail is an affordable and reliable option for shipping packages quickly within 1-3 business days, offering tracking and insurance coverage up to $100. Prices for Priority Mail services start at $8.95 for packages weighing up to 1 lb and can increase based on size and destination. USPS also offers flat-rate pricing for Priority Mail, allowing you to ship a box of any weight for a fixed price within specific size categories. To get the most accurate pricing, it’s best to use the USPS rate calculator or visit a local post office for assistance.