There are many different open source licenses but they all must comply with the Open Source Definition - in brief: the software can be freely used, modified and shared. Programs released under this license can be used at no cost for both personal and commercial purposes. Open Source software is software with source code that anyone can inspect, modify or enhance.
Freeware products can be used free of charge for both personal and professional (commercial use).
Freeware programs can be downloaded used free of charge and without any time limitations.