A 100% deposit bonus is a popular promotional offer in online casinos and betting sites, where players receive a bonus equal to their initial deposit amount. For instance, if a player deposits $100, they receive an additional $100 in bonus funds, effectively doubling their bankroll. This incentive encourages new players to join and explore the platform while providing existing users with extra funds to enhance their gaming experience. However, it's essential to review the terms and conditions, as wagering requirements and withdrawal restrictions may apply.