I stayed with my girlfriend at Hotel Pura Vida while we were in La Fortuna, and it deserves a good recommendation. It is a great, centrally located place that is perfect for a base to explore all the area has to offer. It is three blocks from the center of town, where there are plenty of restuarants, bars, etc, but that puts the hotel away from the bustle of the main drag. The rooms are inexpensive, but very clean and have air condition, TV and hot showers. The beds are great, which cannot be emphasized enough if you are planning to do some of the multitude of tours available. You can book tours right downstairs that will pick you up at the hotel. The owner was very helpful in booking tours and even helped us book a hotel in Liberia the night before we flew out. Highly recommended if you're in La Fortuna for the excitement and not the resorts.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.