MailerLite is my recommended email service provider to start you on the road of email marketing. They are free for up to 1,000 subscribers (with a 12,000 email cap), have great newsletter templates for e-commerce sellers, and earned the ‘Best Email Deliverability’ award.
I’ll have more posts and resources on how to use MailerLite with Shopify and Etsy in the future; until then, they have free online courses available (click on ‘MailerLite Academy’ in the Resources section after signing up) that are crystal clear and walk you through everything.