And for some freegans in particular - for instance, Madeline Nelson, who until recently was living an upper-middle-class Manhattan life with all the attendant conveniences and focus on luxury goods - choosing this way of life involves a considerable, even radical, transformation.

Ms. Nelson, who is 51, spent her 20s working in restaurants and living in communal houses, but by 2003 she was earning a six-figure salary as a communications director for Barnes & Noble. That year, while demonstrating against the Iraq war, she began to feel hypocritical, she said, explaining: "I thought, isn't this safe? Here I am in my corporate job, going to protests every once in a while. And part of my job was to motivate the sales force to sell more stuff."

After a year of progressively scaling back - no more shopping at Eileen Fisher, no more commuting by means other than a bike - Ms. Nelson, who had a two-bedroom apartment with a mortgage in Greenwich Village, quit her job in 2005 to devote herself full-time to political activism and freeganism.

She sold her apartment, put some money into savings, and bought a one-bedroom in Flatbush, Brooklyn, that she owns outright.

"My whole point is not to be paying into corporate America, and I hated paying a big loan to a bank," she said while fixing lunch in her kitchen one recent afternoon. The meal - potato and watercress soup and crackers and cheese - had been made entirely from refuse left outside various grocery stores in Manhattan and Brooklyn.

The bright and airy prewar apartment Ms. Nelson shares with two cats doesn't look like the home of someone who spends her evenings rooting through the garbage. But after some time in the apartment, a visitor begins to see the signs of Ms. Nelson's anticonsumerist way of life.

An old lampshade in the living room has been trimmed with fabric to cover its fraying parts, leaving a one-inch gap where the material ran out. The ficus tree near the window came not from a florist, Ms. Nelson said, but from the trash, as did the CD rack. A 1920s loveseat belonged to her grandmother, and an 18th-century, Louis XVI-style armoire in the bedroom is a vestige of her corporate life.

The kitchen cabinets and refrigerator are stuffed with provisions - cornmeal, Pirouline cookies, vegetarian cage-free eggs - appropriate for a passionate cook who entertains often. All were free.

She longs for a springform pan in which to make cheesecakes, but is waiting for one to come up on freecycle.org. There are no new titles on the bookshelves; she hasn't bought a new book in six months. "Books were my impulse buy," said Ms. Nelson, whose short brown hair and glasses frame a youthful face. Now she logs onto bookcrossing.com, where readers share used books, or goes to the public library.

But isn't she depriving herself unnecessarily? And what's so bad about buying books, anyway? "I do have some mixed feelings," Ms. Nelson said. "It's always hard to give up class privilege. But freegans would argue that the capitalist system is not sustainable. You're exploiting resources." She added, "Most people work 40-plus hours a week at jobs they don't like to buy things they don't need."

Since becoming a freegan, Ms. Nelson has spent her time posting calendar items and other information online and doing paralegal work on behalf of bicyclists arrested at Critical Mass anticar rallies. "I'm not sitting in the house eating bonbons," she said. "I'm working. I'm just not working for money."

She is also spending a lot of time making rounds for food and supplies at night, and has come to know the cycles of the city's trash. She has learned that fruit tends to get thrown out more often in the summer (she freezes it and makes sorbet), and that businesses are a source for envelopes. A reliable spot to get bread is Le Pain Quotidien, a chain of bakery-restaurants that tosses out six or seven loaves a night. But Ms. Nelson doesn't stockpile. "The sad fact is you don't need to," she said. "More trash will be there tomorrow."

By and large, she said, her friends have been understanding, if not exactly enthusiastic about adopting freeganism for themselves. "When she told me she was doing this I wasn't really surprised - Madeline is a free spirit," said Eileen Dolan, a librarian at a Manhattan law firm who has known Ms. Nelson since their college days at Stony Brook. But while Ms. Dolan agrees that society is wasteful, she said that going freegan is not something she would ever do. "It's a huge time commitment," she said.