Wal-Mart is sharpening its attack on Amazon.com.

The world’s largest retailer is trimming its free-shipping pilot program to two days from three, and it’s cutting a dollar off the membership price. Membership is now be $49 per year.

The Bentonville, Arkansas, company began testing the new service last year in answer to Amazon Prime’s two-day shipping, a big part of its domination of the retail sector.

Amazon membership costs $99 a year, which comes with a bewildering array of perks, including household product subscriptions, one- and two-hour Prime Now delivery, streaming music and video, photo storage and more.

“Prime has become an all-you-can-eat, physical-digital hybrid,” Amazon founder and CEO Jeff Bezos wrote in his annual shareholder letter in April. He wants the service to be such a good deal that you’d be “irresponsible” not to sign up, he wrote.

And Amazon has thrived because of it. Analysts say that Amazon Prime members buy more frequently and spend more money.

Wal-Mart’s program, called ShippingPass, allows users to purchase more than one million items, including the most commonly purchased goods at Walmart.com.

“We can offer faster and more affordable shipping because we have a unique fulfilment network that includes new large fulfillment centers, stores, distribution centers and our transportation network,” Wal-Mart said in a company release.

ShippingPass is only a pilot program and Wal-Mart will not say when it plans to extend the service to all customers.