As of today, it costs 49 cents to mail a letter through the Postal Service. You can no longer do what I did, which was buy up a bunch of “Forever” stamps at the old rate at the last minute save that idea for the next increase but there’s one step you can take to minimize your expense:
Discount postage exists primarily because of stamp collectors. When I was growing up in the 1960s, the popularity of the hobby was rising; advertisements for collectible stamps were in every issue of Boy’s Life and in comic books. Increased participation in the hobby generated drove prices higher, so many collectors began to put away sheets and blocks of mint stamps as “investments.”
However, as the decades went by, the interests of young people shifted toward pastimes that required electrical outlets. The demographic profile of the average collector got older, so that now many of the stamps saved as investments are coming back on to the market, and are for sale at prices below their “face” value.
There are other reasons for the availability of discount postage, such as scrap left over by current-day collectors of plate blocks and plate number coils, or mistakenly large purchases for business use (and see the addendum at the bottom of this post), but to make a long story short, postage stamps can easily be purchased today at discounted prices. This is perfectly legal. The stamps were originally purchased from the postal authorities as advanced payment for future service; a stamp issued in 1953 is just as valid for postage now as it was then.
That Addendum suggests that you watch out for very recent stamps being offered at discount; there’s a chance their original acquisition may have been, um, questionable.