usps.priority mail is one of the most commonly used shipping services offered by the United States Postal Service. USPS Priority Mail is known for its affordable rates and faster delivery times compared to standard mail options. With delivery in 1-3 business days depending on the destination, this service provides a balance of cost and speed. Additionally, USPS Priority Mail includes free tracking and insurance for packages up to $100, making it a popular choice for both individuals and businesses sending parcels across the United States. The flat-rate option also simplifies pricing for customers with heavy items.