What is the best free security combo top put on desktop if you do not want to pay for a Security Suite.

There are a number of such applications, but it really depends on your own requirements and operating system.
I'm sure a helpful link will appear shortly.

I myself prefer Zone Alarm free version for my firewall but its not a combo. For that I would use Comodo along with an on demand virus scanner like Malwarebytes. On the PC I'm typing this on I have Zone Alarm free with Clamwin antivirus and Mal;warebytes as well. But neither Clamwin nor Malwarebytes are active virus scanners you literally have to use them to manually scan items or whole drives. I used to use AVG as well as Avira free versions (not at the same time of course) but I didn't like their interfering with my downloads or the high number of false positives they tended to find so I switched to manual types. What you could do is Google "best free firewall and antivirus" and look for a link to a PC magazine review. That way you can get some expert advice and maybe a few comments from the peanut gallery to help you decide.