ConcourseSuite (Concursive CRM). Previously called CentricCRM, it’s a J2EE compliant, open source CRM founded in 2000 by Concursive Corporation – a private media and open source software development company. Equally beneficial for small and large businesses, especially those with complex sales processes. Pricing for ConcourseSuite is a onetime fee of $750 (25 users). Pricing increases as the number of users increase.

Odoo, formerly OpenERP, was started in 2005 and thrives in a unique and open ecosystem by combining the resources of its open source community, partners’ network and resellers. Odoo provides software that is not complex but is still full featured, tightly integrated, runs smoothly, and upgrades seamlessly. Their mission is to provide a range of easy to use business applications.

Odoo is all about ‘extensible architecture,’ with a modular design that lets you mix and match different features. The open source Community Edition of Odoo CRM plugs into the 10,000+ apps in the vendor’s orbit, which are configured to integrate with one another seamlessly.

If you’re in retail, restaurants, or other brick-and-mortar enterprises, you may be interested to know Odoo has a very useful point of sale app. Working with other Odoo apps, point of sale data can easily flow into your inventory management, email marketing, and sales operations.

Available to download from GitHub, OroCRM is an open-source, easy-to-use small to medium business CRM that provides tools for both sales and marketing. Multi-Channel marketing, custom reporting and customer segmentation are some of the tools for marketing, whereas sales management, customer service productivity and multi-channel organization management are some of the tools for sales management.

OroCRM has a reputation as the most flexible open source CRM. It’s based on the Symfony2 PHP framework for web development, which is widely used and well-liked. That means that lots of open source developers find it easy to understand Oro’s code and create new customizations, making it relatively easy and cost-effective to modify the platform to your needs.

Easy integrations with Zendesk, MailChimp, and many other clutch apps are a nice touch too.

Targeted at SMBs, particularly those related to manufacturing, IT, customer service and financial and insurance industry. Daffodil CRM was founded in 2001 and supports both B2B and B2C business models. Based on on-Premise/client server model, it enables unified coordination between sales, marketing, customer service, field support and other departments which interact with customers.

Founded in 2004, it’s a feature-rich, yet cost effective CRM for small and medium businesses. The basic features of vTiger CRM cost $12/user/month, but extras such as additional emails or additional storage space can stack up the cost. A 30-day free trial is available. The features include Sales, Marketing, Customer Support and Calendar.

Vtiger CRM Open Source covers the breadth of customer relationship management features you know and love. You can use it to run marketing campaigns and keep track of leads, customers, and opportunities, handling the sales cycle and daily workflows. Reporting and analytics features are included, and it has a Gmail extension, which is super handy for referencing CRM data and info while emailing.

As you scale up your usage, you can check out the market for add-ons for greater features. It’s the #1 most downloaded Open Source CRM on SourceForge (with 4.5 million+ downloads), so it has a big community of users and developers behind it.

Launched in 2000, Anteil is a light-weight open source CRM that offers basic features for SMBs. Vertical markets include education, governmental depts., NGO’s, fashion industry, financial services, medical/healthcare, and real estate. Anteil can be downloaded for free, the download process comprises of a series of RPM files which need a Linux server.