"I used Big Apple Greeter, which was founded in 1992 to connect visitors with local residents (not professional guides) who love sharing their favorite spots; tours typically last 2–4 hours. Because the service is free and very popular, spots fill up fast—book well in advance since they don’t accept reservations within 10 days of your desired date—and while there is a no-tipping policy, I recommend making a donation to support the program." - Matthew Kepnes