Hi Leslie, that is a great question. One way you could market your product is through CPA’s and accountants who most of their clients are small business owners that may use one of these products. Check the website for these products to see if they have a directory of accountants or certified users. One website that comes to mind is Accountex. I mention them in my How to Find a QuickBooks ProAdvisor article, which you can check out here: https://fitsmallbusiness.com/how-to-find-a-quickbooks-proadvisor/.
Good luck to you!