If you run a nonprofit, you may be able to apply for grants or other free or low-cost funding opportunities. There are multiple organizations throughout the country that focus on providing this type of funding. The approval process can be competitive, but the opportunity is often well worth the effort.
To learn about more grants, consider looking at a site such as Charity Village. Also, talk with colleagues in your field, or consider consulting with a professional grant writer about finding and applying for grants.