Mailtrain is a self-hosted Open Source alternative to MailChimp and other similar mass-mailing and newsletter services. Of course, being self-hosted, it can go only so far – you’ll still need to deal with mail delivery, SPAM filtering, and other modern days “benefits” of delivering mass mailings. But it looks pretty complete in terms of features, so if you want to have full control and don’t mind investing a bit of time in setting up, check it out – you might get a better or at least cheaper alternative.
Here’s an interesting story of moving away from MailChimp to a combined setup of Amazon SES and MailWizz, which resulted in overall 92% reduction of the monthly bill. Given it’s not the same functionality, but if you are technical enough and your requirements are simpler than all the functionality of the MailChimp, this looks like a good alternative.