The Labyrinth sample cart, released by Tokuma Soft, comes in a simple white cartridge with a white label. The cart has no back label.
This is one of the most common sample carts available, and it sells for less than $50 on auction sites.
It’s unclear why this sample cart is so common. Maybe it’s because it was associated with the movie, so more carts were developed and mailed out than for a normal game. Or, maybe Tokuma Soft didn’t keep a close eye on how many it provided to video game journalists and others.