With less than a week to go before the city’s plastic bag ban goes into effect, retailers in the full throes of holiday shopping season are gearing up for the change.

Mayor Martin J. Walsh signed the measure last year, but was worried the ban would negatively impact small businesses and low-income families.

“Some companies could spend as much as 50 cents or a dollar for a bag. That’s a problem. There are people that are on fixed incomes in the city. It’s going to be passed over to the consumer. A dollar a bag or 50 cents a bag or 5 cents on top of all the other charges that people have to pay, that adds up. I have the means to pay, you have the means to pay, but other people don’t,” Walsh told the Herald.

The ban takes effect Friday, Dec. 14, and would only apply to checkout bags used at stores, not bags used at dry-cleaners, newspaper bags or produce bags from inside a supermarket. Retailers, grocers and restaurants are not required to sell any bags, but if they do, it would have to be a reusable, compostable or recyclable bags — and sold at a minimum of five cents.

Congresswoman-elect Ayanna Pressley previously said the ordinance would be a “critical step towards a cleaner, greener and more sustainable Boston.”

Environmentalists agree, arguing the thin, single-use plastic bags available at most retailers contribute to litter and harm the environment.

According to the Conservation Law Foundation, more than 350 million single-use plastic bags are used in Boston each year, most of them ending up in landfills or as litter on the streets.

“This new ordinance protects the health of our neighborhoods and our environment, while at the same time easing the burden on taxpayers and saving local retailers millions,” said organization director Kirstie Pecci.

Skeptics and opponents, including the retail and plastic bag industries, say consumers need to have a choice.

“With Christmas shopping underway, a tourist isn’t going to be walking with a reusable bag,” said Jon Hurst, president of the Retailers Association of Massachusetts. “It’s too bad they’ll have to be charged a convenience to shop local. They’ll be scratching their heads saying ‘Really?’”

Councilor Matt O’Malley, who co-sponsored the ordinance, said that in his conversations with the city’s recycling contractor Casella Waste Systems, plastic bags are problematic to mechanical processors, often gumming up the machinery.

“Twenty tons of plastic bags are thrown into our single-stream recycling system each month,” O’Malley said. “For a very small change, we can make a great environmental impact, help combat climate change, help get rid of litter, and beautify every neighborhood.”

“It’s a cultural shift because we’re so used to not bringing bags in to shop,” said William Christopher Jr., commissioner of the city’s Inspectional Services, whose department would be in charge of enforcing the ordinance.

Neighboring Cambridge, Somerville and Brookline are among 59 communities statewide that have imposed fees or limits on plastic bags.