3.9 percent for USPS Ground Advantage and a larger 9.2 percent for Parcel Select. 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 ...
By the time you buy the right envelope and add insurance, you may be better off going with a USPS Priority Mail Flat Rate Envelope, which costs $10.45. The postal service will provide a free ...