Are corporate accounts free or do they cost? I've always thought that they should charge every big corp that is using their platform as a marketing / customer s

Are corporate accounts free or do they cost? I've always thought that they should charge every big corp that is using their platform as a marketing / customer service tool. Does CNN pay Twitter every time they read someone's tweet on the air? I'm not talking about a "newsworthy" tweet (for example one from a politician's account), but CNN occasionally says, "Let's see what a random person on the internet thinks about this development." Then they prominently focus on a couple tweets. I think CNN (or who ever) should pay for that content.