There are a number of web sites that provide free software for use on your computer. Finding them can be hard, since most people only know about software for sale at retail stores. It's also important that free software be secure and not contain viruses or trojans or other mal-ware. Though most of the programs listed here are totally free, sometimes it helps morale to throw a few bucks their direction as a donation. Open Source and the GNU license basically say you can use the program any way you want it, you must provide the source code if you give it to anyone else, and you are prohibited from selling any part of it.
I have had good luck with these sites that offer free downloads:
