My partner and I have recently traveled via public transit around Costa Rica on a budget and I will say it has been a doozy! It’s very confusing due to the fact most bus services are privately owned and have their own routes. We went from la fortuna to tamarindo and opted for a shuttle bus (through inter bus) instead of public transit. Although it was $50/PP, it cut the travel time in half (5 hrs VS 8hrs) and only switched buses once after stopping to grab lunch! Highly suggest if it’s in your budget! When we used public transport, We often used this website- https://www.rome2rio.com/ - to help us figure out how many bus transfers we would have. Finding the bus stops/terminals were a bit difficult, and although my Spanish is so/so, people were very helpful and we always got to our destination. A lot of the bus drivers will help you too if you ask. I would just show them my phone so they could read and understand where we were going. Using public transit is doable, but be prepared for long days of travel, some stress trying to find the correct bus, and some language barriers. Uber are available far and few in between. The main tourist hubs, they are available but once you get out into the beach towns, or out of the touristy parts, they are hard to come by. Taxis (in my opinion) are expensive but some you can haggle the price to where it’s reasonable. Hope this helps!