Currently you do not have to pay a dime to do a PhD in the Netherlands. In fact, you are almost surely an employee of the university (not a "student") and get a salary of 2300+ EUR (gross) a month.
The 1.8k EUR applies to MA/MSc/BA. If part of the requirement to do a PhD is a to do a MSc degree and the programme is joint you might get a waver from the university for that 1.8k EUR. Also, most Dutch get that money back through the government stipend programme that "lends" people about 250EUR a month and gives them free travel across the whole country. At today's prices this package is worth 4000+ EUR. You only have to pay back that loan if you do not graduate in time (=+1 year of what is the duration of the programme), if you do graduate the loan is considered paid. Foreign students can get on this action by working one day a week, somewhere (incl. TA/RA/etc.). And then there are also various subsidies that students often qualify for. It is not unheard of to see a student in the Netherlands sporting 10k+ EUR income by working one day a week.
>Foreign students can get on this action by working one day a week, somewhere (incl. TA/RA/etc.).
This has changed, I used to get this but since 2014 my job (10 hours a week) does not qualify for it anymore. I think the new regulations allow only people working more than 16 hours per-week (not 100% sure on the exact number).
