Last-mile delivery, third-party marketplaces, voice-recognition shopping, fashion and, now, payments. The battleground between Wal-Mart Stores Inc. and Amazon continues to expand.

Wal-Mart is ready to roll out a credit card with Affirm for online transactions aimed at moderate shoppers — the retail giant’s traditional customer base.

Affirm is being called a potential game-changer by retail experts, who said it provides a faster and better shopping experience that could help expand the wallets of shoppers, particularly those who can’t afford Amazon’s Prime membership fees.

Amazon is believed to be pushing further into the payments realm by promoting Amazon Pay, the 2007 service it launched for consumers making payments online and mobile payments. If Amazon were to expand payment services, experts said it could follow a strategy similar to Alibaba’s launch of Alipay, an independent wallet service.

Affirm has an impressive provenance, it’s operated by PayPal cofounder Max Levchin.

Loans for financing online purchases could have interest rates of around 10 to 30 percent. Wal-Mart said the online application process is easy and that there are no hidden costs or surprises. The retailer claims Affirm will be “more flexible and transparent than any other credit option,” adding that consumers will clearly and easily see their total charges when they checkout online.

Affirm’s digital financing capabilities, and Wal-Mart’s scan-and-go capabilities and synergies with Easy Reorder button, its answer to Amazon’s Dash, are seen as the most powerful aspects of the partnership.

With the loans targeting more expensive products or purchases more than $200, experts wondered whether Wal-Mart would be placing too great a financial burden on consumers with poor or low credit ratings. The retailer has been moving in an upscale direction with its third-party online marketplace, where gowns list in the mid-four figures. Affirm users would probably not be able to afford products on the marketplace.

Amazon in July introduced Amazon Pay Places as a way for shoppers in physical stores to pay using Amazon’s app. Amazon Pay Places frees shoppers  from having to use cash or credit cards and is similar to Google Wallet, which has the digitally stored card data liked to a smart phone.

Amazon and Wal-Mart have battled fiercely through the summer, announcing deals and initiatives almost tit-for-tat. The world’s largest retailer and world’s biggest online and digital retailer made major announcements on July 16. Amazon said it was acquiring Whole Foods, and Wal-Mart confirmed that it was buying Bonobos through, Wal-Mart’s $3.3 billion acquisition. founder Marc Lore, who is president and chief executive officer of Wal-Mart U.S. e-commerce, picked up a string of native online specialty sites, including Modcloth and Shoebuy, and has been pushing technology innovation with Store No. 8 an incubator. Wal-Mart last month said it hooked-up with Google to launch voice-activated shopping via Google Home and Google Express to compete with Amazon’s Echo and Alexa.

Now the battle’s moved to payment services, and it should come as no surprise, considering that payment services breed consumer loyalty.