Why does a volunteer organization need money?

On first glance one might assume that programs that rely significantly on volunteers, like the food bank and tutoring program in our review, would be low-cost programs because of the extent to which their services are delivered by unpaid help. And yet the tutors have to be recruited, screened, trained, and carefully supervised

Nonprofit organizations that have a vision for incorporating volunteer in service delivery accrue advantages over time to their volunteer programs. The support, supervision, and attention that volunteers require, not to mention the logistical aspects of scheduling volunteer labor, are significant responsibilities for an organization and cannot be established casually as an “add on” service. New organizations and organizations interested in adding a volunteer component to existing programs should have access to technical assistance and materials that draw on what strong voluntary organizations have learned as they built their programs

From The Cost of a Volunteer, Grant Maker
Forum on Community and National Service, 2003