When times get tough, Wal-Mart Stores turns into a star performer.

The world's largest retail chain reported April sales that were much stronger than analysts' estimates and its own forecast. Sales at U.S. stores open at least a year rose 3.2 percent in April, when gasoline and fuel sales are excluded.

It was a much better performance than March, when sales rose an anemic 0.7 percent as Wal-Mart blamed cold weather, which hurt apparel sales, and an early Easter.

Another big discounter, Costco Wholesale, said same-store sales rose 8 percent, or 5 percent excluding gasoline sales.

Other big retail chains are expected to show decent April sales, although some of that will be a result of Easter falling in March.

It's clear that consumers are throttling back their spending in the face of uncertainty over jobs and housing prices. The discounters are benefiting from a shift to spending on just the basics.

"The economy continues to get tougher and the paycheck cycle is more pronounced for customers than in past months," said Eduardo Castro-Wright, president and chief executive of Wal-Mart's U.S. business. "As money gets tighter for them toward the end of the month, sales drop more than we have seen in the past."

Total sales at Wal-Mart, including Sam's Club and international operations, rose 9.8 percent in the month, to $29.18 billion. International sales climbed 18.4 percent, to $7.6 billion. Wal-Mart China had double-digit gains in stores open at least a year.

Sales in food and groceries were strong, while allergy season helped sales of medications, Wal-Mart said.

But it's not only the bare necessities. The company also pointed to growth in sales of flat-panel TVs and videogames (thank you, Grand Theft Auto IV).

Wal-Mart will benefit this month from the wave of 130 million rebate checks being mailed out to taxpayers under a $152 billion economic-stimulus package passed by Congress.

The retailer has announced that it will cash economic stimulus checks at no charge.