Agency people often work on market plans for many clients and pick up methods that can be effectively translated to different products and other clients. Many agency people are marketing specialists, yet their advice can sometimes be had for the price of a lunch or a dinner. Your local chamber of commerce represents two major resources. First, it is a source of business friendships, and a way meeting good people in the nearby community, people with similar interests, rather than only through the golf course or bowling alley. Second, your chamber of commerce often has economic departments, or people very familiar with local conditions and statistics, as well as other services available at little or no cost.
Management consultants can be excellent sources of advice and information on an occasional basis.
The great advantage is that they usually offer a wide scope of training and experience. After a few years there is hardly a problem that they haven't worked on. They know what works and what doesn't They become very practical. Your local tax service can provide tax advice on an as-needed basis. Their help can often save you expenses well in excess of their fee.