hello pillarcom,

the question is, how many new members you get every day and how many are active on your site. if you have up to 10 new members a day, a free plan is maybe enough for you. i use smtp2go.com, you have there 1000 emails for free every month, if you need more, plans are starting at 10USD. it is very easy to set it up. if you want, i can help you without any fees.