One bit of overlooked ephemera, that usually is very cheap to come by, is the product manual.
Across the nation, people are buying old doohickeys and thingamabobs….but don’t know how to work them. Why? NO MANUAL! I know I’m guilty for chucking a manual for new things prematurely….but imagine trying to keep one for a product that is 25+ years old.
You can get a nice bit of change for many kinds of manuals. Sewing machines, cameras, electronic devices, cookingware….you name it. If its got working parts, chances are that someone is sitting somewhere scratching their head, trying to figure out how it works.
Look in boxes of papers at estate sales, stacks of magazines…even the “free” box. Most people think they are trash.
Good luck and happy hunting!