A $500 deposit bonus is a promotional offer commonly used by online casinos and sportsbooks to attract new players. When a user makes their first deposit, the casino matches a percentage of that amount, up to $500, effectively boosting the player's bankroll. This bonus allows players to explore a wider range of games or bets without risking their own money. However, it's essential to read the terms and conditions, as wagering requirements and restrictions may apply before any winnings can be withdrawn.