I stumbled across this story about New York City that discusses the best free or inexpensive attractions. Absolutely terrific advice! I plan on printing it out and taking it with me the next time I travel there. I'll summarize it here if you don't want to read the whole thing there:
The subway is $2, Central Park is still free, Times Square at night, Rockefeller Center (Ice Skating, Christmas Tree), Grand Central Terminal, Staten Island Ferry (free), Governors Island Ferry (also free), walking across Brooklyn Bridge, parades, street fairs, some museums with "free hours", and more, more, more.
Not mentioned in the CNN article but worthwhile: Saint Patrick's Cathedral, New York Public Library (3rd largest in the world), and for a small fee - Ellis Island, Empire State Building, Statue of Liberty, American Museum of Natural History, and the Metropolitan Museum of Art.
But when you get to the biggest ticket item, accommodations, the discounted options diminish.
My suggestion, no surprise, would be to stay in a timeshare - rent it! The only real choice there is the Manhattan Club. The size may be smaller than what you are used to if you've rented a timeshare before, but, this is Manhattan! And again, the best bet would be to rent from an owner through www.rentvacations.com. You can probably pick up a weekly or weekend rental there for less than $350 a night and be located at the corner of 56th and 7th Ave. Carnegie Hall is across the street and the theatre district is a few blocks away.