When I ask entrepreneurs and small business owners, it is not unusual for not having any marketing plan. I once read that Sir Richard Branson never had any marketing plan when he started the 1st Virgin business many years ago. In fact in one study of entrepreneurship (I couldn't recall the name of the study) was that as much as 50% of entrepreneurs and business owners don't have a business plan and marketing plan when they first started the business.
Email Marketing: The marketing plan via email is quite an old one. It is an effective and popular way of promotion for many small business owners. Get the email data of your possible customers and send them your customize business emails to let them know what you are offering.