Walmart is expanding its brand-new “Delivery Unlimited” grocery delivery membership program to more stores across the U.S., with plans to reach more than 50% of the country by year-end. The new program allows regular grocery delivery customers to pay either an annual fee of $98 or $12.95 on a monthly basis instead of paying the usual $9.99 per delivery fee. These options make Walmart Grocery delivery more affordable for those who order at least twice a month or more.

The program also gives Walmart a better way to compete with rival grocery delivery services, including Amazon Prime Now/Whole Foods, Instacart and Shipt, all of which offer subscription memberships.

Shipt currently charges $99 annually, and Target recently announced a way for Shipt shoppers to pay a per-order fee of $9.99 for the first time, by way of a Shipt integration on Target.com. Instacart, meanwhile, cut its annual fee to $99 in November. Prime Now is the most expensive option, at $119 per year, but includes all the perks of Amazon Prime’s broader membership program.

In June, TechCrunch broke the news that Walmart’s Grocery Delivery Unlimited program was being trialed in Houston, Miami, Salt Lake City and Tampa.

Those customers responded favorably, which is why the retailer decided to roll out the program to more U.S. markets.

Initially, that includes all 200 metro areas where Walmart Grocery Delivery is available today. By this fall, it will reach 1,400 stores. And by year-end, it will reach 1,600+ — or more than half the U.S.

The program doesn’t offer any other perks, beyond the savings for Walmart Grocery’s regular shoppers. However, it does have the advantage of locking customers into Walmart Grocery and increasing their return rates and loyalty.

Walmart’s Grocery business has grown steadily over the years, and has become a favored alternative to higher-priced services like Instacart, where some products are marked up as a means of generating revenue. Walmart, on the other hand, charges the same online as it does in stores — the only added cost is the delivery fee and tip. (Pickup is free).

Today, Walmart Grocery Pickup is offered at nearly 3,000 stores and Walmart employs more than 45,000 personal shoppers to fill its online grocery orders. Walmart Grocery Delivery, as noted, is on track for more than 1,600 stores this year.

Unlike some grocery delivery businesses, Walmart doesn’t operate its own network of delivery professionals or independent contractors. Instead, Walmart partners with delivery providers across the U.S., including Point Pickup, Skipcart, AxleHire, Roadie, Postmates and DoorDash. It has also tried, then ended, relationships with Deliv, Uber and Lyft.

“We know Grocery Delivery takes convenience to a new level, and our customers love it. With Delivery Unlimited, we’re providing incredible value for our customers, saving them both time and money. When you pair the offer with our everyday low prices and the fact there is no premium, no hidden cost on items, Delivery Unlimited is a really compelling option,” said Janey Whiteside, chief customer officer. “We know the way customers shop isn’t binary, it differs according to what they have going on in their lives. We have an amazing set of assets that help customers truly shop when and how they want,” she added.

Last month, Walmart reported its 20th consecutive quarter of sales gains in the U.S., with $130.38 million in revenue, earnings per share of $1.27 and net income to $3.61 billion, beating expectations. It said at the time that e-commerce sales had grown 37% in the quarter, in large part because of the rollout of next-day delivery and same-day grocery delivery.

Delivery Unlimited will not replace the pay-per delivery fee — that will remain an option for those who don’t want to subscribe. Customers will be able to see if the service is available in their market by visiting the Walmart Grocery website.