How much is it to visit the museum? And do you need to purchase tickets in advance?

25 bucks

Well if leave in New York city you can just give a donation...and you need a state ID

If you live in New York City, it's whatever you wish to donate. If you live elsewhere it's 25 Dollars unless you have visited the Metropolitan on 5th Avenue in the last 2 days. Show your receipt from the other Met, and it's free.