So, the clever investor will be ten thousand forever stamps now, and five years from now, when postage is 48 cents, he will be hanging in front of the post office with a trenchcoat and a fedora ( 
), asking people “psst! Buddy! wanna buy a first-class stamp for 44 cents?”
Technically, if the price of postage went up faster than the rate of inflation, these would be a good bet. But the price of a first-class stamp in constant dollars has been remarkably stable for almost 150 years, aside from a dip in the 50s and 60s.
Convenience-wise, though, it’s a great idea for those of us who take years to go through a book of stamps. (In the rare event that I have to mail something, I usually just throw it in the outgoing at work.)
Related question: At some point in the next few years, USPS will announce that the postage for a letter will be going up again, from 41 cents to some higher price. My guess is that the price of the Forever stamp will be raised on that same day, to prevent people from suddenly stocking up and hoarding. But that’s just a guess – have they made any announcements on this topic? Canadjun, how does it work with your Permanent stamps?
As I understand it:
The price of first class postage is going to be index-linked in the future. Thus, on a certain day, based upon some measure of annual inflation, the price of postage goes up.
The forever stamp was a masterful method of getting the public to accept yearly increases in postage. The price of postage can now be modified without everyone having to buy new stamps, drawing their attention to the sudden shafting by the, er, that is, to the price increase needed by USPS to continue to do the thankless task of seeing to it that hundreds of junk mail circulars are deposited in your mailbox each year. 
Oh, and there are supposed to be limits on how many you can buy at a time, to avoid “investing” in them…
I think it’s only a deal for the small businessman who has enough mail that a bulk purchase would be worth it. I use about 10 stamps per month, if that. I’d have to buy and store a lot of stamps to make it worth my while.
Most of the people I know do on-line payments anyway.
People who buy postage at the post office are a miniscule fraction of the post office’s business. They probably don’t care if you stock up and hoard. The real money comes from places like Bank of America and AT&T who send gazillions of pieces of mail every day. Bank of America isn’t going to rush to send you 6 months of checking account statements just to get it them in before postage goes up.
The post office would rather write off 14 cents than waste its clerks’ time selling you seven 2-cent stamps.
-k-