An online slots deposit bonus is a promotional offer provided by online casinos to attract new players and reward existing ones. Typically, this bonus matches a percentage of the player's initial deposit, allowing them to play with extra funds. For example, a 100% deposit bonus on a $100 deposit gives players an additional $100 to use on slots. These bonuses often come with specific wagering requirements, meaning players must bet a certain amount before withdrawing any winnings. Overall, deposit bonuses enhance the gaming experience, providing more opportunities to win while exploring a casino's slot offerings.