Walmart has fired another shot at Amazon.

In a move that leverages the retail giant’s vast store and delivery networks and expanding online capabilities, Walmart, starting April 19, will begin offering a discount on merchandise that customers buy online and have shipped to a Walmart store for pick-up. Walmart’s new Pickup Discount program will initially be available only on about 10,000 items, but will be expanded to more than one million of the chain’s most popular items by the end of June.

Here’s how it works: Customers shop an item notated with “pickup discount” and ship to their local store for pick up. The shoppers will then receive a discount based on each individual item.

The discounts will vary. Walmart offered a few examples: Lego City Great Vehicles Ferry, which sells for $23.99, will have a pick-up discount of $2.55; a Britax infant car seat that sells for $148.05 will have a discount of $7.40. Larger items will offer bigger discounts: a Vizio television that has a $1,698 price tag will offer a discount of $50.

The new…