American Alliance of Museums
AAM provides Tier 3 museum members with sample business plans.
Free Management Library
The Free Management Library has extensive information on developing a business plan and offers several samples. It notes that for-profit and nonprofit business plans are very similar and offers simple tips that nonprofits can use to translate for-profit language into nonprofit terms.
U.S. Small Business Administration
The U.S. Small Business Administration (SBA) shares resources on developing a business plan, which includes an outline of essential business plan elements and a guide for writing a good business plan.