Is the single-piece price of a First-Class domestic one-ounce letter or flat changing in April 2011?
No. The price to mail a one-ounce letter or a one-once flat within the United States at the single-piece First-Class Mail rate will remain unchanged. The price to mail each additional ounce (or half ounce for 3.5 ounce letters) will increase by 3ยข, however, and the cost to add Extra Services like Certified Mail and Registered Mail to any letter will also increase.
