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The Google App Email service is free for up to 10 accounts.
Update: No longer allows give 10 free accounts – However there is a workaround to get 1 account http://www.hongkiat.com/blog/google-app-mail-for-free/
Besides not having to deal with the overhead of running your own email serves, Google Email also has support to 2-Factor Mobile SMS authentication through Web Browsers and a form of OTP when connecting devices or email clients. Consider turning this on for high security accounts.
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