Plan A  : 10 messages free (Please get this first and test with your domain. If you success send emails you can get below plans.)
Plan B  : USD 2$ ( 500 messages, without duration, connect 2 website)
Plan C : USD 5$ ( 1500 messages, without duration, connect unlimited website)
Plan D : USD 10$ (4000 messages, without duration, connect unlimited website)
Plan E : USD 20$ (10,000 messages, without duration, connect unlimited websites)
Plan F : (USD 50$ unlimited, lifetime, connect upto 3 website)