Rarity and History, Yes - Value, not so much
Recently I changed the way I look at stamps. Instead of collecting for value, I decided to take another approach. Rarity alone does not mean something has a high market value. So why not collect rare or scarce items that have some historical importance?
One area of interest to me is US airmail and specifically glider mail. Items in this sub area can be scarce yet most everything is affordable. I recently acquired a cover with a cachet from the 1929 Detroit Glider Carnival. It was a very exciting time for flight and gliders were the entry path for many future pilots. The cover I found is one of 550 issued that day.
With a subscription to a newspaper archive service, I was able to download some articles and photos from that time and make some personal pages. Oh yes, the cost of the cover was $5.