Before coming to Costa Rica make sure to check with your bank if they have any special credit cards with which you won´t have additional fees while withdrawing money in a foreign country. Over time it will save you a lot of money. In most stores or restaurants, Credit Card will be accepted however make sure to keep some cash around in case you want to buy something from a local market or are suddenly in a need of a taxi.
Travel Tip: If you aren´t already using it try out Google/Apple Pay. Download that application to your phone and type in your credit card info. Now you are able to pay with your phone.