They offer best-in-class features but also the lowest prices and highest allowance for FREE mailing list use: MailerLite, the relatively new e-mail sending and list management service.
A more detailled, dedicated MailerLite Review will be coming up as part of the Pro-Tips series on this website soon.
Until that one is released, and for a review of specific features and details about MailerLite, go to our article featuring more details and functions of the MaileLite service (please scroll down to MailerLite among the other services covered in that post).