There's no way that you can stay in Kraków and not see Wawel Castle. It's the heart and soul of the…read morecity. A national treasure!
The castle grounds, cathedral, and royal residences are all very impressive. You can spend as much time as you want up there taking in the views of the city and the castle complex. There's no admission fee to walk around the castle grounds. It's a small fee to enter the cathedral to see the exhibits, royal tombs, and the bell tower. There are separate fees to enter the residences and the museum. I didn't see any combo tickets offered to see everything. However, I believe you can purchase them online if you know exactly what you want to see on the day of your visit. We just bought our tickets at the cathedral ticketing office. There wasn't much of a wait in the afternoon on a weekday.
We actually visited twice during our stay since our hotel was nearby. The first time was during a walking tour of Old Town. We decided to go back a 2nd time on our own to see the cathedral & gardens. It was a beautiful sunny day.