Which is the best low cost email marketing tool?
Here are some Mailblast, Sendx, Elink, sendpulse, etc
Apptivo, Mailblast, Sendpulse, Sendx these are all good email marketing tools.
There are lots of email marketing tools, some are here: SendinBlue, Moosend, Mailchimp and many more.
Mailchimp and Aweber are the best ones if you are looking for newsletter service.