Salzburg is a day trip from Munich. I will be driving there? Any suggestions for parking? I just plan on leaving my car all day since I won't need it to see Salzburg.
For all day parking, many use the garage under Mönchsberg mountain. For less than 3 hours you may find street parking.
According to ViaMichelin, fuel for a compact car round trip from Munich to Salzburg would be €35. For €20 single person or €28 up to five people you could go from Munich to Salzburg and back by regional trains and not have to worry about parking.
If you do drive, and do not have a Austrian road tax sticker (€7,70), you might be better off (depending on how many of you) to park at the Freilassing Bahnhof (across the river in Germany) and take the S-Bahn or regional train into Salzburg (€2,10 pP each way).