The amount of postage necessary to mail a package depends on the weight of the package, its dimensions, its origin and destination locations and the delivery speed. The U.S. Postal Service offers flat-rate boxes that cost between $5.80 and $44.95 to mail in Aug. 2014.
Customers may use their own boxes, for which postage is calculated individually. Packages that are not packed in flat-rate boxes are weighed to the nearest ounce, and the dimensions must be within the specified ranges. Common delivery methods for packages are Priority Mail and Express Mail. Express Mail is the more expensive of the two, but it ensures that the package will arrive more quickly.