There is a free version of internet security, and a paid version.
I use the free Comodo, and have had no issues with it.
My advice would be to investigate what's available.
If you decide to go with a paid product, see if that product has a 30 day trial.
Install it. Play around with it. Find out how to use it. Is it easy to use, understand? Is the user interface easy to use?
See if it causes any issues with your system. There is no one size fits all, what works for one person or computer may not work for you or your system. If you don't like it, if it doesn't play nice with your system, find something else.
Or try several products, then make a decision. If you decide to pay for one of them, wait until the 30 days is almost up. Some of these products will offer you a discount to purchase.