I think it's like $30 a year with a coupon.
I've used it on Windows XP and now Windows 7.
Seven years - ZERO security issues.
Not free, but peace of mind never is.
I consider Norton AV a very insidious virus in it's own right. It is insidious because it convinces you to buy it and install it willingly.
I use AVG nightly, AVAST installs nicely as a subordinate AV, then I occasionally run Spybot and Malware Bytes. No one utility truly stops or removes them all.
I had McAfee total protection and it was taken control of by some trojan. This trojan actually took over McAfee and will not let it run. Then it wiped out internet explorer. I reinstalled windows XP added all three service packs Inatalled Malware bites ran spybot and the @#%* thing still has control of the computer. I am seriously thinking about taking it out back and using it to pattern my shotgun.