Casinos use a range of PayPal-esque online banking deposit methods. These are companies like MoneyBookers, Neteller, Click2Pay, ePassport, Citadel and MyCitadel. Which you are able to use to speed up transfers in and out of the casino. The way these companies make a living is by charging money on various transactions, depending on the casino they can be cheaper than credit cards. Some casinos (Online Casino, Golden Palace) also offer bonuses for depositting through these methods. I have tried to sumarise the fees that these places charge so you can make a decision which is best for you.

The fees involved with these are obviously going to be bank specific. In my experience Credit/Debit Cards have by far been the cheapest method of depositting. Often there is a charge for international transaction and currency conversion if you aren't playing in your home currency. But they are instant

Wire Transfers aren't instant and incur high fees if they are international. Not worth it.

The more people that touch your money the more they will take. You still get hit with any fees from your banks when you deposit and withdraw from these places. But it might will probably cost less to get it from these accounts to the casino. So if you put in an initial balance and then withdraw your winnings to these accounts to play at other casinos there could be a financial benefit.