how much cost to get in

For being a tourist, I paid 20 dollars

Pay-what-you-wish General Admission is available at ticket counters inside the Museum, and gives access to 40+ permanent galleries, including the Rose Center for Earth and Space. For admission to special exhibitions, films, and the Space Show, a +One or +All ticket is required. These can be purchased in advance over the web, or in person at the Museum. https://ticketing.amnh.org/

No cost, but you should donate.

There is a recommended donation but the museum is admission free