Why are the most important people always charging money?

I keep feeling really impressed by people who make these great, convincing documentaries like Dr. Steven Greer, Charles Hall, and couple others (my enthusiasm is new) and then I find out their either charging too much (imo) for CE-5 or they’re living comfortably from their book sales and only their book sales. It would be stupid not to be skeptical after learning they’re making a killing off of their knowledge of et’s. Are there any people I should know about so I can look them up? I know, I’m needy.