From my experience, stamps are one of those collectibles that people think might be worth a lot of money, but the reality is that their resale value is abysmal. On eBay, I even found a seller who is giving away over 100 stamps for around $5 after shipping. (I actually bought some of these myself, because that’s cheaper than buying new ones from the post office.) Years ago, I met a woman who inherited her late husband’s stamp collection. She used all of them for actual postage, since they still hold value as a way to send mail. One of the packages I received from her was filled top to bottom with his old stamps, because the value was only a few cents each, and she needed an entire box full of stamps just to send something to me!
When it comes to looking for stamps at garage sales, it’s not likely that you will find them too easily. Most people are aware that stamps are valuable, so they tend to research these things on eBay before giving them away. With that being said, it’s not impossible to find a rare and expensive stamp. Just very, very unlikely. The most expensive stamp ever sold was the British Guiana One-Cent Magenta. In 2014, it sold for $9.48 million. And it’s not the only one. Several stamps have sold for over $1 million. But they all have one thing in common, which is that they are very, very rare. And most of them are also incredibly old.