I have trouble with letter series stamps. I have some "G" stamps, but there were apparently several series of "G" stamps, each worth a different value.
Forever stamps? The first series of current forever stamps was issued in April 2007 at .41 each. First class postage is currently .44, 7% higher. If I had banked $100 in 2007, it would have paid less than 1.5% per year or 6%.