No idea where the previous 'search' was done to find antivirus and malware tools. I use several "free" tools myself with no issue, but I also know that there is no "100% effective" tool out there.
On the other hand, 'spysweeper' sure brings to mind pop-up type ads that others have seen, clicked on, and then ended up beinging their systems to me for repair.
Anyway, seems like a bit of a silly post done without prior reseach, so hard to beat down the scent of some sort of spamming going on here. Finding one's way to the SpamCop.net Support Forum, Registering, Validating, and then making one's first post as an advertisement for something that "doesn't cost much" after complaining about other "paid" tools just seems strange. For instance, within this very Forum section, there does exist the
Suggested Free Security Tools and Apps for Windows with tools that are listed and recommended all around the world .... and most, if not all, are exactly "free" (though donations/registrations are suggested in hopes of keeping them going)