A deposit bonus is a promotional offer provided by online casinos or betting sites to incentivize new or existing players to make a deposit. Typically, it involves the site matching a percentage of the player's deposit amount, giving them extra funds to play with. For example, a 100% deposit bonus on a $100 deposit would grant the player an additional $100 in bonus funds. These bonuses often come with specific wagering requirements, meaning players must bet a certain amount before they can withdraw any winnings derived from the bonus.