As of May 2009, 1 ounce costs 44 cents, US
The postage is $1.76 for a standard letter envelope of 2 oz.
You will need postage for the weight of the envelope (probably 2 ounces, for 4 sheets of paper in a 10x13 envelope), plus a surcharge for the size of the envelope. Best guess: $1.19 for first class mail within the United States, as of Feb. 2014.
Since the envelope is 5.25 X 5.25 inches square, the postage is .70 cents for first class. This rate is for an envelope that weighs .5 ounces. The postage may be higher depending on the weight of the envelope.
The postage is standard first class 1 ounce (a "Forever" stamp).
One first class stamp (depending on weight of course).
3 1/2" x 5"
For a first class envelope is cost 44 cents
no, one first class stamp is all that is needed
First class postage for a regular envelope weighing less than one ounce from the U.S. to Greece is $1.20 in March, 2016.
The postage for a 2 oz large envelope within the U.S. typically costs around $1.16 if sent via First-Class Mail. However, postage rates can vary based on factors like the envelope's dimensions, destination, and the specific service selected. It's always best to check the current USPS rates or use their online postage calculator for the most accurate information.
Used currently (2010) for First Class standard envelope domestic postage for a letter weighing from 1 to 2 ounces.
Legally - no. You're expected to pay postage if you re-use it.