I used [sendmybag](https://www.sendmybag.com/) when I had to ship all my stuff from Glasgow to Berlin (and then back as well). Depends on how much stuff you have, but they quote per box/suitcase. Alternatively, I know in Berlin they had men with vans who would make long trips and pick up a couple of peoples' things and do drop offs, perhaps there is something like that in the Netherlands as well?