Ms. Quinn also hailed the legislation as a boon for New Yorkers who forget their cellphone chargers at home “or, if you’re like me, you stepped on it and broke it.”

The price cap exists, she explained, to keep newsstands from growing into minimarts. It does not apply to food carts, street vendors or convenience stands in subway stations, only to newsstands regulated by the Department of Consumer Affairs.

Exceptions to the rule include cigarettes, newspapers, magazines, prepaid transit passes and telephone calling cards. Regardless of price, however, newsstands cannot sell fresh food, apparel, jewelry, handbags, hair ornaments or — though this has long ceased to be a hardship to many vendors — videocassettes.

The cap was last modified in 2002, when it was raised from $2. (Mayor Rudolph W. Giuliani vetoed the bill in the waning hours of his tenure, but it became one of the first bills Mayor Michael R. Bloomberg signed into law.)

Newsstands, which are common in Manhattan but less so in the other boroughs, numbered more than 1,500 in the 1950s, said Robert Bookman, counsel to the New York City Newsstand Operators Association. The number has fallen to 300, driven by the decline of the newsstand’s original stock in trade — newspapers and magazines — and affected by a period of severe regulation, Mr. Bookman said, but it has increased slightly in recent years.