HubSpot

HubSpot offers a full stack of software for marketing, sales, and customer service, with a completely free CRM at its core. They’re powerful alone — but even better when used together.

Free HubSpot CRM
Everything you need to organize, track, and build better relationships with leads and customers. Yes, it's 100% free. Forever.

Marketing Hub
Marketing software to help you grow traffic, convert more visitors, and run complete inbound marketing campaigns at scale.

Sales Hub
Time-saving sales software that helps you get deeper insights into prospects, automate the tasks you hate, and close more deals faster.

Service Hub
Customer service software to help you connect with customers, exceed expectations, and turn them into promoters that grow your business.

BONUS - TRL'S Editor's Note:

They have a fantastic blog with awesome resources - make sure you check it out!