Why do you wanna pay. There are tons of free and good security tools out there. E.g. AVG, Avast, Malwarebytes', Comodo,etc..
Norton is good but is known to have loads of compatibility issues. Unless you have a fast Pc, there's no point going for norton as it will just keep eating up your memory.
I'd suggest you use a free firewall like Zonealarm or Comodo and use an anti-malware, probably Malwarebytes'.
That's my combination of security tools atleast.