I would personally recommend using the Default Firewall you have on your PC, and run ESET NOD32 Anti Virus 4 (which is currently the latest version) along side it. Unfortunately, freeware doesn't always deliver the job properly.. They are free for a reason...
So, wait- let me get this straight- you recommend they use the "Default firewall" which comes <free> with the Operating system, and then turn around and say that free doesn't always do the job?
Am I detecting some self-contradiction?
Also, "free" doesn't mean a thing. a Free program can be great, just as much as it can be bad. Linux didn't become popular just because it's free, but also because it delivers- why else would most web servers be running Apache on Linux if "free" didn't deliver?
or is this somehow just a tenet to apply specifically to the context of Anti-virus programs? if so you're going to have to provide a lot more then empty assertions to convince anybody. There is a lot of free software available that is equal to or better then the same type of software from major vendors.
personally (And I've said this before, Allan has called me a maniac for it, heh) I don't have any AV, software firewall, or other "in the background" program- I do run malwarebytes from time to time, and I use task manager a lot for other reasons so I'm rather familiar with what should and should not be present. my router's firewall protects me from the "packet wind" that seems to constantly come through Internet Lines, and aside from the occasional detection I've only had one major infection, and it turned out that even if I had an AV it wouldn't have been detected anyway. (I was able to use an updated AV to double-check the files I salvaged to see exactly what was infected, though)
EDIT: why have I "survived" without an AV? Why am I not succumbing to the "viruses and malware" that apparently pervade the internet? Easy:
Common Sense. Doesn't cost a thing.