First it is useful to point out who is choosing free software vs. paid programs. When new computers are sold, they are typically pre-loaded with at least one full featured security suite - available as a free trial for a month or two. This recommended paid product is optional and is made available for those who are new to computers, and may not be aware that alternatives exist, or where to go to find them - knowing that most who default into this category will opt to follow recommendations and stay with, and pay for the program.
Contents: What's the difference?