Now they have a Forever Stamp. You buy it today and it will be good until the end of time regardless of future price increases. Sounds like a great way to save literally hundreds of cents, right? My wife (or maybe it was me--these human details are so much dross) posed this question: If I buy a 41 cent Forever Stamp in 2007, am I really saving money vs a 53 cent stamp in 2020 or does it come out in the inflationary wash?
IIRC, inflation is something like 3% per year, but of course we don't have the information on what future stamp prices are going to be. What about history? How closely have stamp prices tracked inflation in the past? Using a history of stamp prices and relative dollar values since 1913 I was able to answer this question. (Notes: All this is based on the first ounce only. I didn't try to go back farther than 1913. For each year, I only use the average dollar value for the year, I didn't break it down by month. For years with more than one price increase, I only report the last one. Since 2007 isn't over yet, I used the last dollar value available, which is September.)
| Year | Apparent price that year | Stamp price in 2007 dollars | % diff relative to today |
| 1917 | 0.03 | 0.49 | 16 |
| 1919 | 0.02 | 0.24 | -70 |
| 1932 | 0.03 | 0.46 | 10 |
| 1958 | 0.04 | 0.29 | -42 |
| 1963 | 0.05 | 0.34 | -20 |
| 1968 | 0.06 | 0.36 | -14 |
| 1971 | 0.08 | 0.41 | 0 |
| 1974 | 0.10 | 0.42 | 3 |
| 1975 | 0.13 | 0.50 | 18 |
| 1978 | 0.15 | 0.48 | 14 |
| 1981 | 0.20 | 0.46 | 10 |
| 1985 | 0.22 | 0.43 | 3 |
| 1988 | 0.25 | 0.44 | 6 |
| 1991 | 0.29 | 0.44 | 7 |
| 1995 | 0.32 | 0.44 | 6 |
| 1999 | 0.33 | 0.41 | 0 |
| 2001 | 0.34 | 0.40 | -2 |
| 2002 | 0.37 | 0.43 | 4 |
| 2006 | 0.39 | 0.40 | -1 |
| 2007 | 0.41 | 0.41 | 0 |
It used to fluctuate quite a bit, but for almost the last 30 years, they've been within a few percents of the same price. And given that even a 10% difference is only $.04, I'd call it fairly constant over the last 100 years (except for a few years).
