What are some alternatives?
Elucify - A completely free software tool that uses crowdsourced data to find business email addresses
Clearbit - Clearbit provides Business Intelligence APIs
KiteDesk - Use KiteDesk sales prospecting software to generate leads from our premium data marketplace. Then reach prospects and build a sales pipeline with organized Lead Lists. Syncs direct with CRM too!
Hunter - Find all the email addresses related to a domain
HubSpot Marketing Free - Free lead capture and marketing tools.
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.