To enter the museum itself is free. However to enter any special exhibition costs. If you enter a special exhibition you can get into the Space Shuttle at no extra costs. If you want to just see the Space Shuttle it is $2. You can get tickets in advance for timed entry, but when I went I just went to the payment booths (next to the Southern entrance), and although it was not advertised they were happy to sell me a ticket to go in and see it straight away.
Free museum, shuttle $ 2, parking varies from $ 10 to $ 16 because it depends on the events they organize at Exposition Park
You only pay the $2 fee to reserve a time
My experience was the same as Adrian's
2 bucks but parking is 12 to 20 depending on day, and if there is a pro game at the stadium it's more like 100
Free but you can get specific times to check it out.
Check with the Calif Science Center web cite but it's not much. Parking is ~$10. Think shuttle was $2 due to printing out reservation ticket. You do need a reservation.
Thanks! Your answer is awaiting moderation.