MailChimp

The most favorite of majority of the email marketers out there, MailChimp is the leading email marketing tools both free & paid. What makes it unique? Well, it comes with smart recommendations feature, which provides marketers with valuable audience insights, enabling them to optimize their email marketing efforts. Not only this, but users also get access to features such as list segmentation, A/B testing, contact profiles and more to get more detailed vision of their email performance.

The free plan lets you send 10,000 emails per month to up to a 2000 subscribers, which is approx 5 mails a month & their paid plan starts at approx $9.99 per month.