Opensource Customer Relationship Management is free in use (though you should always read the conditions) and mostly still in development. This ensures you new versions will be available, without charge! Some of the best opensource systems are to be found below:

Opensource Customer Relationship Management software

SugarCRM
Platforms	Linux/BSD/MacOS/Windows
Software	PHP/MySql
Website	visit SugarCRM website
Download	download (Windows/Linux)
Description	SugarCRM is the premier commercial open source customer relationship management application provider, breaking the rules set by conventional CRM solutions.

HiperGate
Platforms	Linux/Windows
Software	Java
Website	visit Hipergate website
Download	download
Description	Hipergateis multi-company capable, and can be used in a single company, a corporate group or working as an ASP solution capable of serving an unlimited cuantity of single customers.

XRMS
Platforms	Linux/Windows
Software	PHP/MySql
Website	visit XRMS publish website
Download	download
Description	XRMS helps you manage your customer and contact records, track sales opportunities using forecasts and pipelines, ensure timely resolution of customer service and support incidents, and monitor the effectiveness of your marketing campaigns.