Mailgun automatically put me on the foundation plan when my trial ran out. Fortunately after a q support ticket they refunded me and put me on the on documented “Flex” plan which give me 1000 emails free a month. this is not as competitive as SendGrid which allow for 100 emails a day forever…

• https://sendgrid.com/pricing/
• https://app.mailgun.com/app/account/billing/plans

mailer lite might be another email service to check out.