New York is expensive, so you have to be smart

Be flexible
Go in after the crazy summer season, if you're flexible, visit NYC after the kids are back in school. Although NYC doesn't ever really have a true "off-season," it feels less touristy after Labour Day.
The city booms through the holidays, but slows slightly during January and February. The means your access to affordable accommodations will improve.

A wallet-friendly tip to visit a number of NYC attractions
The Explorer Pass offers passes for between three and 10 attractions, including double-decker bus tours, Madison Square Garden tours, river cruises, TV&Movie site tours and more.

Go neighbourhood walking
Bring comfy shoes and get your exercise while exploring neighbourhoods jam-packed with character.
I particularly enjoy downtown areas including the East Village - filled with history and groovy people, the area around Chinatown/Little Italy, and the Lower East Side, and I feel very safe in all of them.
You'll also find your shopping treasures in these neighbourhoods - Canal Street near Chinatown is a bargain-hunters paradise on Sundays, and East Village is crammed with funky shops.
On weekends, Washington Square Park is a great spot to local-watch, and you'll often be treated to free "concerts," played by musicians who work for tips.

Be transit-smart
Depending on how many people are travelling together, it's almost always cheaper to use NYC's efficient, cheap and astonishingly safe subways vs. taking taxis.
The subways are easy to use, will take you just about anyplace you want to go, or - even better, snag a seven-day card and ride subways and buses any place in New York.