Costa Rica’s currency is called “colon” or “colones” for plural, although the US dollar is commonly accepted all over the country. US Dollars are accepted in hotels, restaurants and most of souvenir shops. Nevertheless, it is always good to have some “colones” to pay in small local establishments.
Also, it is easy to go to any bank and exchange your foreign money. All banks will help you exchanging US dollars and almost all will exchange Euros or British pounds. There are also ATM machines all over the country; however, your bank could charge a fee for using one of these abroad. Most credit cards are accepted almost anywhere, and the same abroad fee of your bank could apply.