BENTONVILLE, United States — Wal-Mart Stores Inc.'s e-commerce store won't be offering free unlimited shipping this holiday season, encouraging shoppers instead to buy items online and pick them up at one of its more than 4,600 U.S. stores.

Customers who spend less than $50 on Walmart.com will either have to pay for shipping or arrange to have their items sent to a store, the Bentonville, Arkansas-based company said on Thursday.

The move is a gamble that Wal-Mart can leverage its massive brick-and-retail chain in its fight with Amazon.com Inc. Wal-Mart also is adopting a service that customers check-in with their smartphones when they arrive at the store, alerting the staff and expediting the buying process. The company has been testing the mobile check-in system at its Sam’s Club warehouse stores.

By Shannon Pettypiece; editors: Nick Turner, Kevin Orland.