I spent a weekend hobbying in San Jose, CR, back in 1999. I dabbled in the bar scene, as well as a mp or two. There are a couple of hotel bars in downtown San Jose, where sp's hang out by the dozens. The Blue Marlin, if I recall correctly, was the best known one. You chat one up who catches your eye, and inevitably the conversation will turn to her offering her services and then a little dickering on price. She will ask for $100 USD (this was 7 years ago, so the prices might be a little higher now), but you can usually get her to take $60. You can try to be a hardass and go for $40, but if the girl is any good looking, you can bet some other guy will gladly give her the $60 or even more. Most girls speak a little English, although it does help a lot if you know some Spanish.
After you agree on finances, you take her back to your hotel, and she will have to sign in at the counter. All sp's in CR are registered. No one will bat an eye, as working girls are extremely common and everyone knows that men come to CR from all over the world to sample them.
Services can range from full GFE to short and sweet CBJ and then quick in and out affairs. Although I think this is more a function of the girl than the price you pay, some bargaining can be done. One sp pushed hard for $100 and when I seemed disinterested, offered to do an overnight for that price. This sp did full GFE too, so I was happy with how that turned out.
Another thing I tried was to take an sp on a 2 night trip to the Pacific coast. There are plenty of beautiful beaches in CR, and most working girls love going on a little vacation with you. Choose wisely, however, as remember, you are going to have to spend 48 hours with this girl.