You should also have a look at Dolibarr ERP CRM (https://github.com/dolibarr/dolibarr or https://www.dolibarr.org for portal). Its another free ERP and CRM (GNU GPL v3) which is fuly Open Source (no proprietary version). It is a modular and easy to use ERP and CRM. The addon store contains several hundred of extensions but in most cases you can find all what you need with the hundred of modules available by default with standard distribution.