Some manufacturers such as Okidata, Brother and Panasonic will often call a plastic cylinder or box filled with toner a "toner cartridge".
This is also very common on most medium to large copiers.
These toner cartridges contain only the toner and require other consumable supplies in order to operate within the machine.
Keep in mind that your total cost-per-page will encompass other supplies for your machine.
Be sure to consider the cost of all consumables in your cost-per-page calculation, and not just the toner cartridge.
Panasonic Toner Cartridges
Okidata Toner Cartridges