I recommend that all companies use some sort of 3rd party email system. Constant Contact works well and is not very expensive. You may also consider Marketing Automation software which includes outbound emailing that is integrated into your website. That is, you can see what emails (and what offers) are most effective with your prospect or client database. The systems use behavioral scoring to identify those prospects which show the most interest so that you can focus your follow-up calls on those individuals. These systems include HubSpot, Marketo, Infusion, SilverPop, and many others. Cost typically depends on the number of emails you have. Constant Contact is typically <$100/mos. These marketing automation tools are more like $1,000 to $2,500/mos.