We visited this park during the week. You didn't need to make a reservation for the roman bath but I hear that reservations are needed for the weekend. The baths are individual tiled tubs ( very large) you can go in with by yourself or friends. The spa offers massages for a good price although I didn't have one. There is also a swimming pool and the spring water on site. The spring water is available at the tap anytime, there is no admission fee for that. You can also walk around the park for free. The only time you pay anything is when you want to use a service or go to the pool. The pool is pretty popular among locals so it gets a little crowded.