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.
Offline events like trade shows are highly anticipated growth opportunities for professionals in your industry. Demo your latest product at an appropriate conference and collect signups in-person. Once you're back at the office, import these signups into your contact database. Be sure to send these contacts a welcome email that confirms their opt-in to your list. (See #8 in this blog post for tips on sending welcome emails.)
Confession: We have a serious email marketing crush on JetBlue. And they continue to deliver their lovable marketing in this cheeky email campaign that aims to humorously reengage customers. Every element from the header, to the three witty points, to the actionable, contrasting CTA work together to create a lovable campaign that's promotional without being pushy.