Question: how much does it cost to mail 3 ounces first class?
Answer: It costs $1.00 to send the first ounce of a large envelope and $2.74 and up for the first 3 ounces of a small package. Letters that can't be sent through the Post Office's automated machines have a $0.20 postage surcharge; the shape of the letter determines whether or not it is subject to this surcharge or not.