Besides helping to cover your costs, a job can also give you useful work experience, allowing you to participate in Dutch society and make it easier for you to learn the language.
Students from the EU/EEA can freely work without restrictions. However you must know that as soon as you start a job or a paid internship, you are obliged to register with the Dutch basic healthcare insurance. This applies regardless of how many hours you work per week.
How to find a student job?
The easiest way to find a job is through an employment agency, or "uitzendbureau". You can also contact the student affairs office at your university.