What can I do in New York City this weekend without expensive tickets?

The ferry is the best free thing in the city and the city says so plainly: the Department of Transportation states it is free to ride, with a crossing of about 25 minutes in each direction between the St. George terminal on Staten Island and Whitehall in Lower Manhattan. It runs every day of the year. Departures go roughly every 30 minutes at weekends and at most weekday times, tightening to every 15 to 20 minutes in some weekday peaks. A round trip is a little under an hour of open water for nothing.

Downtown, the African Burial Ground National Monument charges no admission and requires no entrance pass. The visitor center and the outdoor memorial both open Wednesday through Sunday, 10 am to 4 pm, and close Monday and Tuesday — the one scheduling trap in an otherwise free site. Both close on Thanksgiving, Christmas Day and New Year's Day, and both open on several federal holidays even when those fall on a Monday or Tuesday, including Memorial Day, Independence Day, Labor Day, Columbus Day and Veterans Day. The outdoor memorial stays open through winter, weather permitting.

The Met's policy is the biggest single saving available to anyone with New York credentials. New York State residents, and students from New York, New Jersey and Connecticut, choose what they pay for admission, with a floor of 1 cent per ticket.

On the ferry the cheapest seats are the best ones — the outer decks at the stern, where the Manhattan towers shrink across twenty-five minutes of harbor and the Statue of Liberty passes off to the west without anyone having bought a ticket to see it.

The Met's pay-what-you-wish rule has a documentary catch that costs people money at the door. Buying online at a chosen price requires a New York State billing address; New Jersey and Connecticut students can only use the policy in person, with a valid student ID. Accepted proof of New York residency includes a New York driver's license or ID card, IDNYC, a New York library card, or a recent bill showing a New York address. Turn up with none of those and you pay the full posted rate.

• Saturday morning — The ferry's 30-minute weekend headway means a round trip slots neatly into a block of 2 hours before anything else opens.
• Saturday afternoon — The African Burial Ground's 4 pm close is early for a downtown site, so it has to come before, not after, a long lunch.
• Sunday — Monday and Tuesday are the monument's closed days, which makes Sunday the safer half of a weekend for it.

Free does not mean unlimited: the ferry timetable is published with a note that schedules may change without notice, and a missed boat at a 30-minute headway costs half an hour on an exposed terminal. The burial ground's week of 5 days removes 2 days outright, and its holiday openings are listed as exceptions rather than the rule. Pay-what-you-wish admission at the Met is residency-gated, so visitors from outside the tri-state area should budget the standard price rather than plan around the 1-cent minimum.

The things-to-do answer in this group lists the full admission prices you are avoiding, and the when-to-visit answer gives the month-by-month Central Park normals that decide how much of a free weekend can be spent outdoors.