Weight of your mail piece determines the postage required to mail. Take it to your local Post Office and they will quickly answer your question correctly.
44 cents an ounce to mail a first class letter in the USA.
42 cent for an ordinary first class letter.
First-Class Mail International Letter $1.05 (as of August 2012, but it increases every year or so).
Currently, May 2015, in the US one ounce of First Class mail is 49 cents.
Just a forever stamp to mail it in the U.S.A
First Class Mail was delivered with three cents in postage.
How much does it cost to mail a letter to St Croix VI 00820
15 cents
6 cemts
44 cents to mail it first class
10 days
To mail a first class letter from the US to Canada is $1.15 as of 2014. This is for 1 ounce or less. More than an ounce will cost additional.