Hi,
I have checked the primary required as in project description. Initially you want to communicate with your customers like a notification of podcast. If you want to send less than 20K email in a month, you can go with mailchimp. One of the best in industry with a 12000 free emails in month. It only takes a setup work approx 50 usd if you have a domain name.
We can discuss further if you want to evaluate more options, Thanks.