I was at my local Rhino Video Games store talking with the assistant manager. In those corporate-run stores, they'll get boxes of used games shipped in from headquarters to sell, as opposed to all of their stock coming from walk-ins. And apparently Rhino figured it was too much hassle/money to worry about game values varying by factors like condition, box, manual, etc. So there's a set price for everything regardless of what condition it's in. And apparently they only deal with loose cartridges.
So the other day, this store gets a shipment of used games to sell. One of them was Legend of Zelda, first release. Marvelous condition. In the box. FACTORY SEALED. The girl stocking the shelves that day thought nothing of it. Ripped off the cellophane. Opened it up. Box, manual, sleeve > in the trash. Put the cartridge on the shelf with a shiny new price tag, $12.00.