20 STABILO EASY Original Refills for under 9 euros

Our son (primary school) likes to write with the Stabilo Easy. This is easier and cleaner than with a "real" filler.
Logically, also needs the Easy Ink Cartridges (Refills), which are not cheap generally. There are, however, 20 for under 9, - Euro (unit price below 45 cents). This is significantly cheaper than all offers, I have found otherwise. I am satisfied Topp.

Irritated me only the item description. Once is "3 Refills" is mentioned, then of "20 St". What to look for here the "3", is my Rätsel.Richtig would "STABILO EASYoriginal 20 Refills medium blue ink".