What are some alternatives?
Elucify - A completely free software tool that uses crowdsourced data to find business email addresses
Hunter - Find all the email addresses related to a domain
HubSpot Marketing Free - Free lead capture and marketing tools.
Email Hunter for Chrome - Find all the emails related to a domain with just one click
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!
Google Contacts - Contacts helps you stay in touch with the people you care about.