The volume discount has long been a staple of New York City commerce, permeating bakeries, electronics stores and, for more than a decade, even the city’s transit system with a simple pledge: You buy something, you get something free.

But that era may be coming to an end, at least in subways and buses.

On Wednesday, Joseph J. Lhota, the chairman of the Metropolitan Transportation Authority, said the agency had discussed the merits of eliminating or reducing the 7 percent bonus offered to riders who buy pay-per-ride MetroCards of at least $10. Any change could be an important piece of a looming fare increase, which is expected to take place by March 1.

“Do we really need to give that level of a discount?” Mr. Lhota said at the Plaza Hotel on Wednesday during a discussion hosted by Crain’s New York Business.

The bonus, he said at a news conference after the forum, was a relic from the age of tokens, when the authority considered adding a free ride for those who bought a 10-pack. A volume discount like this was never put into effect until the MetroCard era, in 1998, when riders received a 10 percent bonus on purchases of at least $15 — buy 10 rides at $1.50 each and get the next one free.