Most “Free Downloads”  are really 30 day trials. I wouldn’t install a free trial unless I was serious about incorporating that software into my company. It is too much work to get a program up to speed to utilize a free trial as your discovery. Do the other steps laid out in the other articles and then do a free trial when you’ve got your decision pretty much made.

These programs are said to be free. I haven’t “vetted” them. Check them out before you download:

RationalPlan Project Server

A Ruler For Windows

Ace Project

Microsoft Project Viewer