How much money to bring to Virgin Islands?

I'm going Aug.24th to the 30th with my fiance. Non all inclusive resort. We will be going to the supermarket and getting drinks/lunchmeat/bread/chips for lunch and packing something for the beach. We do want to go out for dinner a couple times, get some drinks from the bar, do a couple excursions and go to the aquarium, as well as Coki beach and Magen's Bay. We also want to do a St.John tour. How much do you think would be a safe amount to bring for both of us? I also know taxis add up. We are staying at the Emerald Beach Resort...alot of people have suggested we walk from the airport to the hotel...is it really close walking distance? Any input would be appreciated! Thanks!