No, that's not true.
I've mentioned it in a few comments now, but for events within Netherlands there is no cost - you can either have your (free) vaccination check or you can get a free PCR test and have a time-limited entry code. PCR tests for this purpose are always free in NL.
And the Netherlands is covering the cost of PCR tests for travel through July and August, by which point any adult who wants a vaccine can have had one.