MailChimp.com and InfoUSA.com can provide you with several free mailing lists for your clients. FreeLists.org is another website that showcases free mailing lists for email marketing purposes.
Email marketing with an email list is advantageous because you have complete access to the list on your own email services. Other marketing websites and systems may experience downtime, but because you have access to the list, you do not have to worry about missing any marketing campaigns. The email list is also based entirely on permission because your subscribers allow you to post to them. This establishes your authority and encourages your subscribers to learn more about your services.
No matter how frequently you market through social media websites, you are supplementing your efforts by reaching out to customers through their email addresses, especially when you synergize your email marketing campaigns to work with social media outlets. Additionally, it may be more effective to market through emails in some circumstances, as your customers may have additional social media fees running through page, which can result in your message getting lost amidst a sea of other updates. Email marketing is also an affordable way to begin advertising before you explore other mediums of marketing your brand.