Megabus, which regularly offers fares for as little as a dollar, is now giving free bus trips to the first 100,000 people who book travel between January 6 and March 20 of next year. Forty thousand of those seats are set aside for New York-bound trips; the rest of the tickets can be booked to any place Megabus travels (including Baltimore, Boston, Detroit, and Philadelphia). Tickets can be reserved now through the Web site; use the promotional code “GETAWAY.” There is a booking fee of 50 cents, and the offer is obviously subject to availability.