Has anyone used a service like ZeptoMail ? (https://www.zoho.com/zeptomail/)
They even have an official WordPress plugin called transmail - https://wordpress.org/plugins/transmail/
This is excellent as it costs only $1.50 (1 credit) per 10,000 mails but there's one catch - credit(s) expire in 6 months which is no good for very small WP sites.
