Good news! That stack of 10¢, 15¢, and 20¢ stamps totaling $100 in face value is worth $1500. Sell! Sell! Sell!
The bad news is that you have to wait until the year 3081 for that headline to come true.
Discount postage with gum continues to sell in the 50% of face value range. There is still a glut on the market. Some dealers have stopped buying mint postage. Some have lowered their offers even more (read: if you are willing to give it away for almost nothing, they will take it).
This will not carry on forever. At some point, gummed postage is going to disappear. After many of these stamps have been used for postage, the market is going to change. When will that be?
There is still a lot of discount postage coming on the market today. If the supply was shut off today, I estimate that there is enough discount postage on hand that the market will not change much for another five to ten years. There is a huge supply still waiting to be used.
Self-adhesives dominated the stamp production around the year 2000 and gummed issues dropped to almost nothing. Realistically, I say it will take about 50 years before today’s stock of gummed stamps sitting around are mostly disposed of by heirs.
It will not be a sudden turn for all issues. For example, the 3¢ and 4¢ stamps from the 1940s and 1950s will disappear from holdings of mint postage. In time, these issues will start to rise in value, albeit very slowly. You see some evidence of that now. A few of these issues had low print quantities and/or increased demand. That handful of issues brings over face value today when sold. In time, other issues will slowly move up in value too. Today they bring 5¢ per copy. In ten years, it will be 15¢ per copy. And so on. You get the idea.
In time, today’s issues will rise in value too. For example, Scott #3390 is the Library of Congress issue and one of the last of the stamps issued with gum. It was issued in 2000. Today it is 50% of face value. Thirty years from now, the topic of libraries depicted on stamps becomes a hot category, demand rises, and this issue begins to sell for more than face value.
No one reading this today will live long enough to see our $100 in face value turn into $1500. We will see some stamp issues that gradually turn the corner and become worth more than just face value. There are a few issues like that today. More will follow over time.
I think the market for discount Forever stamps will subside over time. Why? With denominated stamps, some sellers wanted to get rid of them because they do not want to fool around with 1¢, 2¢, or 3¢ stamps to make up the difference. It is too much trouble. They decide to unload them and forget about it. There will always be large holdings that are not easily used for postage. However, the smaller accumulations of a few hundred dollars or less – people will use them (or give them away to friends or family members).
Today you have sellers who have a small stack of 20¢ gummed stamps and they will unload them. In the future, those kinds of sellers will disappear. If they have Forever stamps, they are good for postage no matter what the rate is. Small stacks of postage like that will probably never reach the discount postage market. Sellers will just use that small stack of leftover Forever stamps for themselves. Unusually large holdings though may still come on the market because sellers will not be able to use that many stamps in a reasonable period of time.
If you are holding on to $100 of gummed mint stamps hoping for a $1500 payment, you will need to find the Fountain of Youth. Or if you die, consider cryogenics and have your body brought back to life 1000 years from now. This assumes people are still interested in stamp collecting in 3081. However, that is a different story for another time.