Art supplies is too broad as a category to search.
Many shops stock pens, pencils etc, kids painting sets etc, but very few actually have oil paint and accessories. It’s a gap in the market in Montenegro.
in Herceg novi , there is this shop, the only one I have seen that has all things needed for oil painting, ,boards,brushes, solvent etc, as well as graphic art supplies, toys etc. Good all round shop. I bought enough to keep me painting for about a year.
I travel back and forth to uk and want to mention that they don’t allow any paint to be taken onto the plane.