vtiger CRM is a free, full-featured, 100% Open Source CRM software ideal for small and medium businesses, with low-cost product support available to production users that need reliable support. vtiger CRM is a widely used product with thousands of users in dozens of countries. It has a vibrant community of users driving the product forward, and contributing to it's development. Over a million copies of vtiger CRM have been downloaded by our users.

vtiger CRM provides a complete set of CRM capabilities, such as
1. Sales force automation
2. Customer support & service
3. Marketing automation
4. Inventory management
5. Activity management
6. Security management
7. Calendaring
8. E-mail integration

Features:
Sales Force Automation
1. Lead Management
2. Account & Contact Management
3. Opportunity Management
4. Sales Quotes

Customer Support & Service
1. Trouble Tickets
2. Knowledge Base
3. Customer Self Service
4. Online Knowledge Base

Marketing Automation
1. Campaign Management
2. Mass Mailing
3. E-mail Templates
4. Mail Merge Templates

Inventory Management
1. Products Catalog
2. Price Books
3. Vendor Management
4. Purchase Orders
5. Sales Orders
6. Invoices

Activity Management
1. To Dos, Meetings & Calls
2. Recurring Events
3. Shared Calendar
4. Activity History
5. E-mail Notifications
6. Notes

Productivity Add-ons
1. Email Client
2. Outlook Plug-in
3. Office Plug-in
4. Thunderbird Extension
5. Customer Portal
6. RSS Feeds

Reports & Dashboards
1. Key Metrics
2. Customizable Reports
3. 20 Pre-built Reports
4. 20 Pre-built Dashboards
5. Report Folders

Product Customization
1. Custom Fields (10 different data objects)
2. Pick Lists
3. Custom List Views
4. Drag & Drop Modules

Security Management
1. User Management
2. Profiles
3. Roles
4. Groups
5. Currency customization
6. Organization-level Access Control

The license of this software is Free, you can free download and free use this customer support software.