I have a mastercard debit so same thing. You use it exactly the same as a credit card. It's great cause I can't spend what I don't have and no monthly repayment to worry about. It's great for internet shopping cause if anyone steals your number there is no money to steal. I basically keep it at a zero balance and only put on money when I need to. I'm with the commonwealth and you can set it up linked to your main account or have a completely seperate one (I have this). I could also apply online through online banking so didn't need to go in. They charge me $4 a month account keeping fee. I don't know though if having it linked to the main account would save fees.