Unfortunately, there is no telling what the best anti-virus software is. They all have their advantages and disadvantages. Considering the ratings are slightly varying from month to month, it would be hard to establish the best one.
Currently, Windows natively has its own anti-virus Windows Defender, and it works relatively well. The majority of the popular providers have free versions of their software to test out, and they also do the job. As for anti-virus, I recommend Comodo, Avast, Avira, Bitdefender, Kaspersky or Norton. All of them proven formidable. But in all honesty, if you do have windows, Windows Defender is your best option, since it doesn’t use that much additional resources, while third party antivirus solutions might.
With anti-virus, you usually will need to run anti-malware software. Not every single anti-virus has the full package included. Any of the popular software solutions will be solid as well. My recommendations towards ADWCleaner, Malwarebytes, Hitman Pro, I used them all, they did the job. Something to be aware, Malwarebytes paid version provides full suite including Anti-virus and Anti-malware. If you are going for a paid version, you won't need anti-virus solution.
For in browser solution, you could use an Adblocker to protect you from malicious ads, uBlock takes this one for me.
But when it comes to the internet, no software will protect you 100%. My tip would be to be aware of what you are browsing and downloading. Do not click suspicious links, avoid shady files. Additionally, be careful with emails, a lot of malware is spread through fake/malicious emails. That is the best way of being safe out there. Good luck!