All taxis, public transportation, and many restaurants only operate in cash, and are expected to be paid in Dominican pesos. If you have a foreign currency, they might accept it (they might), but they won't give you exchange in the same currency and they might not give you any change. Dominican Limousine has taxis equipped with ramps and hydraulic lifts that operate in Santo Domingo and Punta Cana. There are plenty of places to find taxis in Santo Domingo, such as Parque Colón and Parque Duarte, outside of all high-end hotels and throughout the Colonial Zone.
The crystal clear waters of Bávaro Beach make it ideal for snorkeling, and many hotels on the Strip include snorkeling equipment during your stay. For the more adventurous, there are also numerous dive spots.
In addition to accommodation, you can expect food, drinks, activities and entertainment to be included, without having to pay more for it. A true all-inclusive vacation should never have unexpected costs and allows you to enjoy a worry-free vacation without having to open a tab.