There are three ways of how to see Prague Castle. 1. For free, which takes about two hours including the Castle Gardens. There is also no admission to the part of the St. Vitus Cathedral. 2. With the B ticket which covers the most important historical sights of the castle, such as the St. Vitus Cathedral, St. George's Basilica, the Old Royal Palace, and the Golden Lane. 3. C Ticket which allows you all of the above and also some of the castle museums.