how much is postage for a letter
As of October 2014, the postage rate to mail a first-class, letter-size envelope through the United States Postal Service is 49 cents for the first ounce. For large first-class envelopes, the rate is 98 cents for the first ounce. Each additional ounce per envelop costs 21 cents.
The postage cost to send a letter to Mexico depends on the weight of the envelope, according to the U.S. Postal Service. Postage for a letter that weighs no more than 3.5 ounces costs $1.15 to $2.86 as of January 2014. A letter requires between three and six 49-cent stamps.