The retailer said customers can purchase the gadgets at their new prices starting Wednesday. Wal-Mart said it is also cutting the price of the iPhone 5c to $29.
Customers who wish to buy the devices must get them with a two-year contract from either AT&T or Verizon. Wal-Mart said the rolled back prices will be available for at least 30 days.
Previously, Wal-Mart sold the iPhone 5s for $145, the GS4 for $99 and the iPhone 5c for $45.
Additionally, customers who buy any Samsung smartphone between March 9 and March 22 will also receive a $50 Wal-Mart gift card.
The Galaxy S4 price cut and $50 gift card promotion were likely spurred by Samsung's late February announcement of the Galaxy S5, the company's next flagship smartphone. The GS5 will go on sale in April.