SBA's Business Plan Tool
U.S. Small Business Administration Online Business Plan Tool is FREE.
Create a free account, and let this site guide you through the steps of writing a business plan. There is no charge, and the advice, structure, and plan design have been around for decades. This is a classic style business plan, good for applying for business loans, or mapping out a classic business.
A Wikipedia article on Business Plans will give you an overview of the content of a plan without having to register at the SBA site.