You should then choose the amount that you want to deposit in your new account.If you want to use Mastercard, this is where you click on that option. You should then be taken to a screen where you can choose your payment method. After you have opened your account at the online casino, click on the Add Funds Now tab or its equivalent.So how do you make a payment at a casino where Mastercard is accepted? The process is usually very simple, much like it is with Online Poker Sites Accepting PayPal, as you can see below. T&Cs apply Making a Payment with Mastercard at an Online Casino Qualifying bet cannot be placed in-play or cashed out early. Place a qualifying £25 fixed odds bet at odds of 1/2 or greater.