Amazon is dialing up efforts to win over customers that typically frequent rivals such as Walmart: low-income shoppers.

The online retail giant, whose vast North American retail business growth has slowed in recent quarters, has announced new offerings aimed at the poor, most recently a new credit card for consumers trying to establish or rebuild their credit. It has also added half-price Prime memberships for those on certain governmental aid programs, as well as a method for consumers to reload their online accounts with cash at convenience stores. It has even recently looked at buying Boost Mobile, a prepaid cellphone wireless service that caters to low-income customers, from Sprint.

The moves could help Amazon attract a new customer group that has long been loyal to Walmart and its more than 4,700 U.S. stores, many sprinkled throughout rural and lower-income communities. But it also comes attached with some risk for the shoppers: For example, Amazon’s newest credit card’s interest rate tops 28 percent.

“This kind of greed makes the poor even poorer,” tweeted frequent Amazon critic, Sen. Bernie Sanders (I-Vt.), adding that he and Rep. Alexandria Ocasio-Cortez (D-N.Y.) will introduce legislation to “outlaw it.”

Amazon spokeswoman Paruul Batra declined to comment on Sanders’s tweet. Amazon is “committed to making it easy for all customers” to use Prime, Batra said. (Amazon founder and chief executive Jeff Bezos owns The Washington Post.)

Over the past two decades, Amazon has grown from an online bookstore to selling everything from toilet paper to couches. Revenue grew rapidly as the company persuaded consumers to do more and more of their shopping online, eventually approaching nearly half of all U.S. online spending, according to analyst estimates. But in the first three months of the year, revenue growth in the company’s core North American business slowed to 17 percent from a pace that topped 46 percent in the same period in 2018.

Meanwhile, Walmart and Dollar General, known for rock-bottom prices, have maintained strongholds in rural towns and low-income communities where they are often the only big chain retailers. In 2013, Walmart executives said an estimated 18 percent of the country’s food stamps had been redeemed at the company’s stores, amounting to about $13 billion in annual sales, a number analysts say has stayed constant. Walmart also offers check cashing, bill payments and other financial services for shoppers without bank accounts or credit cards, and it recently brought back its holiday layaway program.

Now Amazon is trying to attract those customers, too.

They may seem like an odd target for a company that owns premium grocer Whole Foods and sells Kindle e-readers that can cost as much as $350. But they could help propel growth of Amazon’s Prime membership program, which has largely saturated wealthy households in the United States. Those customers tend to spend twice the money their nonmember counterparts shopping on the site, according to analyst estimates.

To attract lower-income consumers to its fold — many of whom don’t have easy access to credit cards, a safe place for delivery or the Internet — Amazon needs to change buying habits for shoppers who are accustomed to making purchases at brick-and-mortar stores where they can use cash or government-assistance programs to pay for items. Amazon is betting programs such as its new credit card will persuade consumers who rarely, if ever, shop online to give it a shot.

“It’s about diverting customers away from Walmart,” said Andrea Leigh, a former Amazon executive who is now vice president of Ideoclick, a Seattle firm that helps brands sell on Amazon.

That means catering to customers such as Mary Harrington, who took two buses from her home in Southeast Washington to a Walmart on the other side of town on a recent weekday morning. Harrington, 60, makes the hour-long trip each way two or three times a week because she likes shopping in person. She has never bought anything online.

“I’m on Social Security, so I can only buy so much,” Harrington said. “You can’t find better prices than at Walmart.”

Consumers with household incomes of less than $50,000 are less likely to shop online than their more affluent peers. Those households do about 3.4 percent of their shopping online, compared to 9.7 percent for households with annual incomes of $50,000 and more, according to economists at Stanford University.

Meanwhile, roughly half of all U.S. households had Prime accounts in January, the investment firm Cowen & Co. estimates, based on quarterly surveys it conducts. But membership growth has slowed as the market among wealthier customers becomes more saturated.

Low-income consumers are the group least likely to have Prime memberships. Just 31 percent of households making less than $25,000 are Prime members, compared to 60 percent of households making more than $150,000, according to a 2016 Cowen survey, the last time the firm released data on Prime members’ household income.

“They are trying to pull the levers to boost that number,” Cowen analyst John Blackledge said.

Amazon began offering discounted membership for $5.99 a month to its Prime frequent-shopper program last year to the roughly 20 percent of the U.S. population that is signed up for Medicaid. That’s in addition to the discount it already offered to people who obtain government assistance with cards typically used for the Supplemental Nutrition Assistance Program, often called food stamps. The company usually charges $12.99 a month for Prime memberships.

Amazon — along with Walmart — is also part of a pilot program by the U.S. Department of Agriculture to allow SNAP participants to select and pay for groceries online.

Amazon’s new card, called Amazon Credit Builder, is aimed at customers trying to establish or rebuild their credit. To obtain it, consumers need to deposit funds, and the amount they deposit becomes their credit limit. Cardholders who are members of Prime — which includes speedy shipping as well as video and music streaming — can earn 5 percent cash back on purchases.

The card’s 28.2 percent interest rate is higher than the median for retail cards, 25 percent, according to Ted Rossman, an industry analyst for CreditCards.com.

The online retailer has also added Amazon Cash, a reloadable prepaid card for customers who don’t have credit and want to shop on the site. Customers can reload their accounts at 7-Eleven and Coinstar machines, among thousands of other locations.

Earlier this year, Amazon said it would begin accepting cash at its Amazon Go stores after mounting criticism that the cashier-less convenience stores discriminated against those without credit cards, bank accounts or smartphones. The cashier-less stores ask shoppers to pay using an app on their smartphones.

As Amazon tries to grow its customer base, it faces increasing pressure from Walmart, which is in turn encroaching on the online retail giant’s turf by chasing upscale shoppers in more urban areas. Walmart acquired Jet.com for $3.3 billion in 2016 and subsequently bought up a number of higher-end niche brands, including ModCloth, and Bonobos. Walmart.com has become more upscale too, offering brands such as Brooks Brothers, Calvin Klein and Ray-Ban.

Last year, Walmart introduced JetBlack, an invitation-only personal shopping service in New York that competes directly with Amazon by offering personal shopping services over text message. One year in, the company says members spend an average of $1,500 a month on the service.

Renae Merle contributed to this report.

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