open sources

For  the first time, I just really had a chance to look for available programs that are open sources.  Why is it not more well known just how many opportunities are out there on the internet for free programs?  I remember someone in class making the comment that people stay away from open sources because of fear with viruses and spyware.  However, free is free.  I wish I would have known about a lot of this stuff when I was an undergrad.