The plans are based on the number of "products" but this is never defined. This isn't defined in your help center. In fact, the help center returns every article for every search, just changing the ranking.

I already pay for a help center. My tools work with my help center. I've got links to my help center. You're asking me to throw out everything to start fresh on a platform with almost no information. Honestly, this is the wrong play. Don't build your own, update your users' existing sites. I'd gladly sign up for a trial of a service to manage my help site for me. But I'm not getting a new one without a lot more confidence that it's worth it.