What is the best free software for email marketing?

[J]

it really depends on whether you have a list.

if you have a list that is confirmed double opt in that you either built, rented, bought or something of that nature the there are hosting companies that will allow email broadcasting of a sufficient level to be acceptable. with an account all you would need is the ability to write a little html code to send html emails, or notepad to write generic emails.

http://bypasshost.com/compare-packages/

however if yours is a junk email list that is harvested emails that you wish to send UCE emails almost everyone reputable will turn you down. reason it harms their site and its reputation.