Is priority the same as flat rate? It has many of the same features, but it comes in two versions, where you can either pay based on the weight and destination of the package or pay a flat rate ...

The price of a Priority Mail flat rate envelope (size 12-1/2″ x 9-1/2″) will jump from $10.45 to $10.78 while the Priority Mail Express flat rate envelope (size 12-1/2″ x 9-1/2″) will jump ...