demo floppy disk (3.5" when those really were floppy), with the installation instructions stapled to it....
LOL
But that would have been a 5.25 inch floppy with the cardboard outer. Yes they were literally floppy.
The 3.5" was a big advancement. It had a plastic case and doubled the storage capacity from 360KB to a whopping 720KB. I paid four dollars each for the first ones I bought (in 1988?) Back then four dollars could buy a nice lunch and still have change.