Really great park! Parking is free and the grounds are dog friendly. I went in the morning right after they opened so it wasn't too hot and the school groups hadn't arrived. I recommend going around then, the parking lot is expansive, but it's easier to navigate when empty. The cannon firing was especially cool, but the first firing wasn't until 11am (park opens at 9). But that meant there was plenty of time to lazily stroll around the different exhibits and end with the cannon. The peacocks that roam around are definitely a highlight!
The park and beach access is free; to get out onto the pier itself to "sightsee" is a dollar. They have fishing equipment you can rent and fish on the pier as well. There's a smattering of benches on the pier itself to sit and look out. The view from the end of the pier is great and definitely worth it - we were able to see some dolphins swimming off the coast! The pier could probably use a fresh coat of paint though.
The entrance fee is now $6.95 if I can remember correctly, but still well worth it. If you've done other FL lighthouses, this one is a little more difficult as it only has one railing, but the view from the top is fantastic. There's a great woodsy trail to walk and there's a heartbreaking exhibit with rafts that have washed ashore, presumably from Cuban refugees. The lighthouse is tucked away so the area is nice and quiet and off the beaten path. There's lots of great places to sit and picnic nearby and there's an adorable lighthouse cat that hangs around the main house.
It's not all it's cracked up to be ;) but if you needed a stop to stretch your legs, this is a great place to do it with a fun picture to take too. There's a big field right next to it if you've got someone in the car who needs to run around and burn off some energy.