Mailchimp has turned out to be chock-full of functionality for my first experiments with a drip email marketing/educational campaign for my resume/LinkedIn Profiles/career counseling biz. Free up to 2000 subs and a ton of different templates to choose from.
I haven't used it yet, but I'm planning to use it for a personal project. I like that it has built-in support for Markdown.
Seva (formerly ConvertKit) if you need more automation and you need to manage different segments.
https://mailchimp.com/pricing/