Hi The entrance fee was $10 US and they take US money. The park is very basic and small compared to the others and does not have food or drinks available and bring alot of water with you! (You may also want to bring toilet paper, there wasn't any in the washrooms when we were there). As for the guide- that is completely up to you if you feel it necessary but be very careful as we were told there are quite a few untrained people and some were in the parking lot waiting for tourists. We chose not to use a guide because of this and their fee ($25-40 US/person), just take your time and its amazing what small things you will see. We noticed the guides walking through very quickly and missed alot of things we saw. If you are going to any of the other larger parks you may want to guide it then. This isnt the park for monkeys although we did hear the Howlers. We liked this park better than Manuel Antonio simply because you dont have to wait in line to get in or see something (was more zoo like). If you choose to not use a guide we noticed they placed small flags/ markers at locations where they have either spotted or the usual hangout for an animal so they are not finding them all on their own. This park was amazing for insects, butterflies, (a morpho landed on my leg), flora, lizards, and we actually saw a poison dart frog just by taking our time. It was actually more distracting to have the groups with guides making alot of noise and not looking down to see the small stuff. If you want my opinion, grab the trail map at the entrance and explore on your own- more relaxing and you will see more. Hope this helps and i envy you- would go back in a heartbeat!