so this information may be dated.
Depend on how long you will be staying. We paid for our accomodations and diving (Castle Comfort / Dominica Divers) by VISA. Lunches and dinners were extra and also paid by VISA.
The second week we spent there we travelled around and could pay most things (vehicle from Island Rental, most restaurants) by VISA. But I would keep at least $100 to $150 / day cash/traveller's checks for non-VISA (or credit card) restaurants, dive tips, park fees, souvenirs, emergency, etc (depending on how many in your group). THe jungle tram only took cash (even though there was a VISA sign. I always paid cash for gas and had very few problems with traveller's checks. The pharmacy only took cash.
THe bank (Royal Bank) was a pain - the bank machine refused to give me a cash advance - even though the Royal BAnk is the one I deal with at home!!!
Don't forget to have cash for the exit taxes, taxi driver tips, maid service, and most important - beer at the gas stations.
Hope this helps.
