The Orientation Year Permit is a 1-year permit that allows recent graduates to live and work in the Netherlands without a permit for 1 year.
You can apply for this 1-year permit within 3 years of your graduation, and application costs € 285. It is important that you have obtained this permit by the time you start any activities after your official graduation that would require you to have a work permit. If you start an internship with an employer in the Netherlands after graduation without having obtained an orientation year permit, you will be working illegally. Before you apply for an internship, check whether you need to be a student to fulfil the position.
You need to apply for this permit at the Immigration and Naturalisation Service (IND). Read more about this option on the special page about the Orientation Year Permit.