Just wanted to throw out some more information about the earlier comment in this thread about exchange rates and using ATM/credit cards:
Visa/MasterCard do not have anything to do with ATM withdrawals, unless you are making withdrawals on your credit cards - which I do NOT recommend (talk about finance charges!). The ATM networks, the bank who owns the ATM, and your bank are the ones who have an opportunity to charge fees. Check with your bank before you travel to find out what fees are charged for international cash withdrawals. The bank who owns the ATM is also required to physically post any fees on the ATM or prompt you during the transaction.
As for credit card purchases, some issuing banks very inconspicuously charge an exchange fee. You should always call your credit card company to ask if they include any fees for purchases made internationally or in another currency. You would be shocked at how much you may end up paying. For example, many banks include a 3% surcharge in the exchange rate. Others charge nothing. 3% may not sound like a lot, but I'm willing to bet that many of you put that last hotel bill on the ol' Visa card, and a $1000 charge would be an extra $30 in one transaction...
BTW - one more note while talking about plastic: Be sure to call your card companies before you leave to inform them that you will be travelling to Bonaire. You would not want them putting a block on your card for suspicious transactions while you're over there.