What are the best advertising techniques for small business? Compare the return on investment (ROI) of outdoor advertising versus print and visual media. Word of Mouth is still the best form of business advertising, unfortunately it is also the slowest type of promotion. On premise outdoor signage is the most effective and least expensive form of advertising for a retail location compared to any other type. For more information on the outdoor sign products manufactured by Signtronix visit www.signtronix.com