What currency should I bring, and can I use my cards?
US dollars and cards go a long way here. When colones are handy, and the easiest way to get them.
Costa Rica's currency is the colón, but you can travel happily on US dollars and a card.
Cards are taken almost everywhere you will go: hotels, restaurants, tour companies and most shops. Tell your bank you are traveling before you leave, and if you have a card with no foreign transaction fees, this is the trip to use it.
US dollars are widely accepted too. Bring some smaller bills for tips and roadside stops, since change for a large note is not always on hand, and you may get your change back in colones.
Colones are handy for small local purchases. The easiest way to get them is a bank ATM, which gives a fairer rate than exchanging cash at the airport or a hotel.
If you like to know the day's rate, Costa Rica's central bank publishes it on its homepage (in Spanish): https://www.bccr.fi.cr/