If the standard-sized letter weighs less than 1 ounce, only one first-class stamp is required to mail a letter from New Jersey to Tennessee. For each additional ounce of weight, 21 cents is added to the initial postage of 49 cents, as of June 2014.
U. S. Postal Service domestic first-class shipping rates do not change with distance. Mail can be sent between any two points in the United States for the same amount of postage. Letters can also be mailed via priority mail, which travels faster but also costs more. The pricing of priority mail is also dependent on distance unless the letter is shipped in a flat-rate envelope.