Going to all the museums that NY has to offer can be extremely expensive. We have a long list of ones we want to explore during our two months in the city but I have also noted alongside them the times that they are either free or pay as you wish prices so we can experience as many as possible.
The Whitney is one of our favorites we have gone to so far. On Fridays from 7-10pm it is pay what you wish (which can be nothing) to go inisde. We were basically the last ones in the museum as it was being closed down at 10pm and had such a great time.