Room for rent
You could check out the website www.househunting.nl which is also available in English. In general you will have to deal with agencies paying in advance the first mouth + two more mouths and a percentage, (one as deposit, and the other as mediation fee plus the 16 -18% in taxes). Find a room in Netherlands is certainly not easy as in Spain where you can deal directly with the landlords or even with tenets where you can save tones of money.
Good luck!