Went to CR last summer-- Nosara, or Playa Guiones which is the beach break we stayed at. Houses on the beach were 400K plus, off the beach but walking distance were 200K-250K. Up in the hills farther from the beach around 100K for farily new construction. I've seen cheaper houses in the sub 100K range, but they are not near the beach.
Nice surf in Nosara, and the people were very nice. Lots of gringos.
Buddy works at the Century 21 office there in Nosara: www.century21nosara.com