The large companies allow 10.000 emails/month for free and the base service is pretty much the same. Take your pick of Amazon SES, Mailgun, Mailjet, Postmark, SendinBlue, SendGrid, SparkPost ... (via https://github.com/anymail/django-anymail).
Hey, depends on what you're looking to do. Are you looking to send Marketing or Transactional? Coding your emails in HTML or wanting drag and drop capabilities? I use Mailjet for all of the above.