u meant they still got extra fee? I tot what we bought is what we get on prepaid card?
Answer in general is no. Do not know who issues prepaid cards in Singapore, but in States they are issued by "Tony Soprano's Credit Corporation" most likely - they will charge you fees in addition to the VISA/MC on every single occasion and there is no way to avoid it.
The right way to deal with the situation is to get a ATM card from your banking institution and have low amount of funds on the account - couple thousand $ max to cover cash only needs while you are overseas. Get necessary cash from ATM and use it for small expenses. This will also protect you if the card 'walks away' somehow.
For larger expenses get a credit card which promotions and extra cashback/miles/points for overseas purchases to offset the exchange rate fees.
You'd get more responses and suggestions if you ask the question at credit card forum.