I have had virus protection on my mac laptop, as I always had when I had a PC. All my fellow mac owners say it’s not worth renewing it when it expires?

apparently my "Norton Security Online" has been cancelled by At&t. now i need to find a good security software program with virus protection and advanced firewall.
and if i do find one should i Uninstall the one that is cancelled?

I first had avast antivirus but it said it was out of date and needed an update, so i tried to update it but it wouldn’t work.

So i downloaded avg(the free version) and my windows secruity thing pops up and says "your virus protection is out of date" RIGHT AFTER I DOWNLOADED IT.
>:l

How do i fix this?

I pay alot of my bills online and was wondering if it is safe to use w/ this virus protection.

I tried Windows Live One Care virus protection recently, but my trial just expired. I was wondering if there was a similar virus protection (one with real-time and automatic updates) that I could download for free or free to try. And if so where can I download it at? Any suggestions would be greatly appreciated!