I've never used the product, but after looking at their site, I'd hazard a guess that you're not going to have the best time centrally deploying and managing that product. If you have a very small number of client computers you might "break even" on the amount of time you're going to spend tending to the product versus the cost of buying something that can be centrally deployed, upgraded, and managed.
Basically, you're going to pay for an antivirus product either in licensing fees or in your sweat and toil. (smile)
As an aside: If your users are running as "Administrator", you will get a "return on investment" from getting them to run as limited users. Many viruses, worms, etc, are severely hampered in their ability to "get things done" by a user who is running with a limited user account. You'll get some benefit just by doing that, even if you don't end up deploying anti-virus software.