I just wanted to give a mention to Best of New York as I’ve successfully used both them and their sister site Best of Orlando to save hundreds on tickets to attractions and shows over the past couple of years.
In NYC I especially like the CityPass, which gets you into a whole slew of attractions over nine days. TIP: If no one actually puts a date on the CityPass (IE you buy it online), no one know when the “9 days is up! YMMV, of course, I milked mine for over a year, visiting one or two attractions each trip instead of trying to marathon mile my way through the Big Apple.
I’m sure you’re aware of Living Social, Groupon, and Restaurant.com for local deals, but do you check them for your destination when you travel? About a month before your trip, I recommend signing up for the email list for your destination. All have a strong presence in Orlando, Vegas, New York, and pretty much anywhere. Local tourist attractions often use these services as a way to dump unused tickets or drum up local business for tours.
Recently in NYC I saved over $20 at the Museum of the Moving Image and over $50 on the Harry Potter Exhibit. On Las Vegas’ Groupon page were 1/2 off Grand Canyon tours and Mentalist tickets. Last year in Orlando I got GCs for Walt Disney World Swan and Dolphin restaurants at Restaurant.com. Five minutes to check these sites out could save you a bundle!