Before coming to Costa Rica, you should know a little bit about the money used and how much exchange it is to your local currency.
Let's start with what money it is called in Costa Rica:
The Colón (named after Christopher Columbus, known as Cristóbal Colón in Spanish) is the currency of Costa Rica. The plural is Colones. The ISO 4217 code is CRC.
The denominations come in the following forms:
Coins: 5, 10, 25, 50, 100, 500
Bills: 1000, 2000, 5000, 10,000, 20,000 and 50,000
In Costa Rica, the Spanish word for Money is Plata. Plata actually means Silver and the traditional definition from Spanish is Dinero and used in the other Central American countries. Either one works here but if you want to speak like the Ticos, go with Plata. The Spanish word "Mil" means Thousand in English. 5 Mil is Five Thousand.
US Dollars (USD) are accepted in Costa Rica.
Exchange Rates vary when not using a bank to handle your exchange and can get a little confusing. The basic rule of thumb is to pay in the same amount that you are given. For Example:
In Restaurants, they always charge in Colones (CRC), therefore pay in CRC to get the best rate.
In Tours, this is usually charged in US Dollars (USD), so at this moment you want to pay in USD.
Up to date Exchange Rates can be found HERE on the bottom left of the page. Simply choose USD or EURO and enter it in to see the exchange rate. You may need to click the ARROWS to get the proper exchange.