The official language of Costa Rica is Spanish, so, the Costa Rican word for Butterfly would be Mariposa. I did a search and La Mariposa" hotel.. If you click here you will see the rates:
http://www.lamariposa.com/rates.htm (The cheapest that I saw was $130/night - you can also click here:
http://www.centralamerica.com/cr/hotel/mariposa.htm