I have a question on Website making

So I came up with an idea for a website a while ago, and I feel the need to make it. However, I have never made a website before and I had a few questions:

A) Are those free website builders okay for making a website, or are they awful and I need to pay money for a good looking site.

B) How can I make revenue on it? What I want to make for a website should be free for anyone to use. However, if I want to keep it running, I might need some form of revenue. I know that there are commercials, but I don't want to clog it with adds on the website (maybe one or two).

C) How can I keep the website free of spam, viruses, or anything else that would infect people's computers? Is that something that people who make the websites put on there, or are there ways to keep people from putting it on there?

Thank you for your time in answering any of these questions.