Tickets are free. Some exhibits dont require a ticket at all. The main floors of the museum requires a timed ticket, no cost. You can get in advance or just show up and wait in line.
You can get advanced ticket online for $1 or queue at door but not guaranteed as there are limited tickets for the main attractions...i advise getting the tickets at the entrance for free the day before or just go early and hope the still have them availabke same day.
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