Located in the San José airport the Global Exchange currency window is running the most lucrative cash exchange business in Costa Rica. This is because its easy to exchange foreign currency at any bank in Costa Rica, and none charge any fee or percentage. Global Exchange, however charges substantial fees. Also, there is absolutely no need to use this service. All the taxi drivers at the airport will gladly accept United States Dollars, along with hotels and restaurants in San José.
General advice is to bring a stack of U.S. $20 bills for your initial purchases, and then visit the bank or ATM when its convenient. Alternatively, look for the branch of the Banco de San José near the check-in counters in the airport departure area.