It is compulsory for all people living in the Netherlands to insure themselves. You are however free to choose which health insurance company and which package you apply for. For the basic insurance you will have to pay a premium to the insurer which varies between companies. The premium exists partly out of a nominal fee for individual insured people (approximately €1100 per year per person). Employers pay an income-related contribution to the scheme. You can also choose to buy supplementary care and more extensive cover.
In order to shop around you can visit www.kiesbeter.nl (Dutch site)
For children under the age of 18, basic insurance is free of charge.