Credit cards, PostePay, PayPal, Skrill, Neteller, ecoPayz, Paysafecard, Entropay, and Paysafecard are all acceptable ways of payment. The webpage should clear up any questions you have about whether or not these techniques may be used for withdrawals as well. The casino has a minimum withdrawal requirement of $20 and a maximum processing time of 7 business days. Remember that, as at any regulated casino, you can't request a withdrawal from King Billy until you've finished the registration process by sending in the necessary documentation.
In the "Responsible Gaming" section of the casino software, you will find a number of very useful tools for complete control over your gaming activity, including the ability to set deposit limits, review your gambling history, and self-exclude for a specified amount of time, among other things.