You can expect to pay about $145 per person for your entrance but expect that you are going to spend more money on food, the souvenirs, and so many other miscellaneous things that you will find inside the park. A lot of people are saying that it is worth it though because they get to experience an adventure that they will probably never experience anywhere else.
It also helps that Harry Potter is very popular even if the last book was released years ago. There are just some stories that people will always remember for their whole lifetime. Take note that the visitation price sometimes rises depending on the number of people who would like to enter the park.