Offering work experience can be as rewarding for the employer as the student.
Many employers find having a visit from a keen, enthusiastic individual who's eager to learn, has a very beneficial effect. The student may have useful related skills, and while they should not be considered as a replacement to a full-time employee, there are many roles in which they can be extremely valuable. The need to explain systems and processes also offers you the opportunity to consider and improve them.
Many employers are extremely busy, and receiving a work experience student can seem like one more thing to worry about. But taking some time to set up a work experience scheme and a system of dealing with requests can actually help to improve your productivity, as well as being a valuable contribution to the training of potential future employees.
Whatever your area of business, it is quite probable that there is a student studying a related course in your area. Contact a college near you, or one specialising in your area of work, if you would like to discuss in more detail how you can get involved.