I got mine a couple of years (like 5, 6 years) ago in Almere (Nederland muziek). After that I only saw one in a store in Utrecht, near the crossing the Amsterdamsestraatweg/marnixstraat ( I think) buts that also many years ago, the store is right behind the busstop, but i can't remember the name...
Best bet would be marktplaats.nl but I only see them rarely.