Bitrix24 is total business management software that's 100% free.
You get over 35 free tools, like CRM, tasks, document management, project management, time management, business process automation, invoicing,
collaboration, absence management, email marketing, virtual PBX, shared calendars, company directory, HRMS and much more. Available in
cloud and as software that you can install on your own server, it's ready to be used in less than 30 seconds.
If you are interested in buying self hosted editions of Bitrix24, which come with API, CMS and source code, and can be easily customized
and integrated with other tools, please download trial version here.