Newsletter Plugin

Hi Guys, I have a new blog but I want to have an Newsletter subscription plugins that will send out 20 recent posts to the users on the site. Also, this plugin MUST enable me to import emails. I have over 200,000 emails I want to import into the blog so they can also receive the daily updates which will be sent out from the blog automatically as soon as news posts are added on the blog.

Pls note that this plugin MUST be a free version (I don’t want premium or trial version).

Thank you.