As I told you I normally get my theatre tickets for free or I probably wouldn't go as often.
I have never stayed in a hotel in NYC but it doesn't surprise me that they are pricey. Don't forget that a lot of people staying at hotels are there for business so the prices are high. Also I think September may still be considered part of the summer tourist season.
You may have gotten cheaper prices if you booked a room in White Plains or someplace else in the burbs. You would be able to take the train into NYC but you would lose the convenience of getting around and I think the trans to Westchester stop running at some point.
Derfie, you can't take it with you so splurge a little!