A tourist entry visa costs 25 euros per person at the airport, it covers you for 30 days in Cape Verde.
If you are on a package holiday your tour operator may include the price of the entry visa in with your package, but you need to confirm this, some people keep confirmation with them that shows if it was supposed to be included. However, on occasions if the list of people that the Police at Passport Control have been given by the tour operator hasn't been updated, it may not have your name on it. If this happens the Tour Reps may ask you to pay for a visa and tell you to keep your receipt so that you can claim it back.
If you don't have cash in Euros you may need to ask to use the ATM. Please make sure your bank knows you are using your card in Cape Verde. Some cards may not be accepted at ATM's.
If you arrive at Sal or Santiago airport during the day and before 3p.m. (unless it's a weekend or a public/national holiday) the bank at the airport may be open and you can exchange your currency for euros, but make sure you take your passport with you as well as the currency you need to change.
NOTE: The Cape Verde Government have announced that the requirements for European Nationals to obtain a Tourist Entry Visa from 2018 may