If you have an income, you pay tax 
You receive an income if you are working. You can earn money with an employment contract, working freelance/with your own business, or doing both. Different taxes have to be paid for different kinds of income.

Read more about taxes

The difference between being self-employed and working freelance
The Netherlands Tax and Customs Administration (Belastingdienst) treats people working to order in a very different way from the employed. The Belastingdienst also makes a difference between artists working freelance and being self-employed in their own business.

Both freelancers and self-employed people can apply to the Tax Administration for a Working Relationship Declaration (Verklaring Arbeids Relatie, VAR). Some clients ask for a VAR to clarify the tax status of your working relationship.

Read more about working to order

Income and social security
If your are temporarily out of work, or work less, as a (former) employee, you will probably be entitled to claim benefits. You paid a premium for these social insurances during employment.

If you are self-employed, or work freelance,  you are not entitled to these insurances. They can take out private insurance to cover this risk.
Artists can, under certain conditions, claim benefits from the Artists'  Work and Income Act (Wet  Werk en Inkomen Kunstenaars-uitkering, WWIK).

Read more about social security