I am reluctant to sign up for HBO MAX because it doesn't say if it is free or not. If I press add channel am I automatically billed. And what the **bleep** is going on with their customer support. They apparently can't be bothered to offer customer support.
No. It's $14.99 a month.
Adding the channel does the same thing as adding any other channel - it installs it for free, but when you launch it, it will ask you to sign in with your paid account. Just like Netflix, Hulu, Prime, etc.
HBO has mentioned offering some content at a lower cost with commercials, and perhaps even a free version with limits to the content. But so far it's all talk. You either need an HBO subscription through a provider, such as a cable or satellite company, or with a direct subscription with HBO.