I recently purchased a garmin nuvi 760 (from Amazon) because it (a) has bluetooth fulfilling a need to have a handsfree for the car and (b)there is a CR map available for it.
The CR map came from TravelbyGPS http://www.travelbygps.com/premium/costa/rica.php and was an additional $149. I was able to download it w/o problem and install as well.
We were in CR over Christmas and it performed quite satisfactorily.
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