In a cash game (a game where people just play poker), the casino takes a rake (a percentage with a certain cap) from each pot that is wone. In other cases, like in card rooms, you might get charged by the hour. Either way, you’re basically paying a “rent” to have a table, and in the case of a casino, a dealer, plus what is presumably a game that is safe (from cheating, from players trying to rob you afterward, etc.).
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