If you have a list of voluntary, ‘opt-in’ email addresses, the best way to handle them is with a marketing solution like MailChimp, which can be integrated into your social site or webpage. I can create plug-ins or widgets for email capture to embed on your site. I can also set-up a tablet or mobile device with a Mailchimp email capture screen.
I do not recommend “buying” email lists from any source. This is spam. Your emails should be volunteered on your site or in your business by individuals. This seems difficult and time-consuming, but it works better in the long run, and keeps your company’s reputation safe and amiable with your customers. Word-of-mouth recommendation will strengthen, as well as online reviews.
Right now the quickest alternative to email marketing is a Facebook page. More and more traffic is moving into the small business end of Facebook, and I think eventually emails themselves will be replaced by Facebook’s social environment of posts, comments and messaging. Having a Facebook page with a proper URL and attentive administrators is becoming increasingly important.