It is always a good idea to bring some dollars to tide you over until you can go to the bank. Do not expect to be able to cash a personal check. Major credit cards are accepted in most large stores in the main cities. ATM's are available. No shots are necessary to come to the country.
Medical facilities are numerous and dependable.
Unlike other developing countries, the water is safe to drink in most areas. Be careful on buses and in crowded areas. Do not leave valuables or personal documents in a parked car. Travelby air within the country is adequate and inexpensive. You can drive for 3 months with a valid driver's license issued in your own country.