Whatever form your newsletter takes, know it’s just one of many touchpoints. But it’s the most direct way to speak to the people who may be your clients someday consistently with no marginal cost. Focus on delivering value to them—even if there’s only 10 of them at first. For most service businesses just two or three new clients for the year is such a big payoff that nurturing a small list of interested subscribers thoughtfully is completely worth it. However, if you sell low cost products then quantity is important and building a huge list would be your goal.
Mailchimp offers a forever free plan which allows you to send 12,000 emails for up to 2,000 subscribers. This plan is fairly limited because you don’t features like send-time optimization, advanced segmentation, multi-variate testing, etc. You are also required to display their branding in your email. Last but not least, support is restricted to email only, and you may find it not as helpful.