If you're planning a bit of sightseeing head to Old City Hall— just one of the monuments in City Centre Salzburg. You could also start your cultural experience by heading over to the museums in the area.
If you want to give your credit card some exercise, head out to Getreidegasse in City Centre Salzburg. It's also full of great shops and restaurants, so you can spend the afternoon having a wander. Splash some more cash at Salzburg Christmas Market and Linzer Gasse.