The article number stands for the manufacturer's name of the ink cartridge and the No. indicates the manufacturer's abbreviation on the label.
The purchase prices for original cartridges can be found in the column Original empties, those for already refilled ink cartridges in the column Refilled empties.
If you click with the mouse on the button in front of the respective article, you will get to the detail page of the corresponding empty ink cartridge. With the button you can add the respective article to the sales cart.