I think the best way to organize money and paying for daily expenses here in Cabarete is to use the ATM machine to withdraw money from your bank in the States/Europe. This gives you the best exchange rate, better than bringing cash and changing it here.
You can withdraw 10.000 pesos per day, in 2 times of 5,000 pesos. That is 300 USD.
A small bottle of water is like 10 pesos, like 30 cents.
A bottle of Presidente is around 30 peso, in the market, less than 1 dollar.
A breakfast at the bakery should be less than 100 peso , less than 3 dollars.
A Dominican lunch of chicken and rice is 90 pesos, that is 2.65 dollars
A typical nice dinner out, with drinks, can be around 500 pesos each, that is around 15 dollars, but you don't have to spend that much if you are on a budget, and you can spend a lot more if you want to splurge!
Hope this is helpful and you can email me for more info, or just pass by the kite school when you arrive, we know all the inexpensive places to eat and drink!