What is the free (cheapest) service for sending 100,000 emails?

Question

Email

There is a base of 100,000 subscribers, you need to send them an email, tell them how best to do it, there is an option to make 50 accounts in MailChimp if they just don’t ban you, you just don’t want to pay $ 1000 somehow. Advise how to proceed

Answer 1

so it will not work, either to pay, or to do your own.
Make your own cheaper, and for subsequent mailings will be

Answer 2

Pay 1k