Jim,

I'll save some money. Don't worry about the weight of the envelope or the note.

The first ounce costs .34, the second and third ounces cost .23 each.

so postage on this will never require .68 it will be .57 for 2 ounces or .80 if the weight of your package is 3 ounces.

Of course I am too lazy to go to the post office for .23 stamps so I tend to put .68 rather than .57