Mastercard operates like any other credit card, whereby the cardholder is granted x amount of credit with which to make transactions worldwide. A minimum payment on the outstanding balance is due every month, failing which will lead to additional interest charges. Mastercard is a very convenient form of payment as it is accepted by most vendors and online merchants around the world.
Mastercard is not an available option at all online casinos, especially when depositing from the US. If you prefer to deposit with Mastercard then we recommend you check with the casino first before signing up for an account.