You are already providing design services, marketing materials and maybe mailing services. Offering website and online services are a natural fit.
Adding websites and web services to your service offerings is a natural fit since you already provide marketing and sales materials to your customers.
Local businesses, non-profits, consultants and any type of service business are great candidates for this service
By selling website services you are keeping yourself top-of-mind with your frequent customers as well as the customers that use your services infrequently.
There are no costs to you.
One reat thing about website services is that they are billed monthly, every month, for as long as the customer uses the service. This will provide a consistent predictable income on top of your other sales.