The primary purpose of a transactional email is to convey information regarding the action that triggered it. But, due to their high open rates (51.3% compared to 36.6% for email newsletters), transactional emails are an opportunity to introduce or extend the email relationship with customers or subscribers; to anticipate and answer questions; or to cross-sell or up-sell products or services.
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.
Honor opt-out requests promptly. Any opt-out mechanism you offer must be able to process opt-out requests for at least 30 days after you send your message. You must honor a recipient’s opt-out request within 10 business days. You can’t charge a fee, require the recipient to give you any personally identifying information beyond an email address, or make the recipient take any step other than sending a reply email or visiting a single page on an Internet website as a condition for honoring an opt-out request. Once people have told you they don’t want to receive more messages from you, you can’t sell or transfer their email addresses, even in the form of a mailing list. The only exception is that you may transfer the addresses to a company you’ve hired to help you comply with the CAN-SPAM Act.