5 white tote trays like they had back in school to store all the various manuals I've had in various places around the house in cardboard boxes. One for hiking gear, one for electronics, one for kitchen stuff, one for car detailing stuff, one for household appliances...

Had to get the "teacher size" so it'd be big enough to lay a regular piece of paper in flat: Click

I didn't think they'd be hard to find, but they were. Wanting a index card holder for labelling on the front made it difficult.

I didn't get lids for them because it'd just be one more thing I had laying around the house. They stack without them well enough.

Cheap, attractive (enough for storage in a closet), and easy, these things are perfect and make my house a little cleaner.