Many Broadway theaters sell tickets for standing room, located directly behind the orchestra seating. The catch: tickets are only available on the day of the performance and the show must be completely sold out. Tickets usually cost between $15 and $30. Check with specific box offices for details.
A handful of Broadway theaters and most Off-Broadway theaters rely on volunteer ushers to work during performances and it's easy to lend a hand in exchange for a chance to see the show. Make a reservation in advance and then arrive about an hour and a half before the performance for a debriefing from the house manager. After you show paying theatergoers to their seats, settle down to enjoy the performance for free. You might be asked to stick around for a bit afterwards to scan for stray playbills or lost-and-found items. Call the box office as procedures (and dress codes!) vary.
Want to do it? Check our partial listing of theaters with volunteer ushering.