COLUMBIA - Wal-Mart stores around the state were open early this morning, one sign of the retailer's ongoing excitement about the state's fourth annual back-to-school sales tax holiday.

Retailers expect consumers to line the aisles looking for deals on clothes and especially big ticket items, such as computers. Apart from discounts already offered this time of year, shoppers won't have to pay the state's 5 percent sales tax -- 6 percent in York County -- through the weekend. The holiday lasts from 12:01 a.m. today to 11:59 p.m. Sunday.

Retailers seem ready for the tax holiday, filling Thursday's newspapers with ads promoting back-to-school sales and noting the tax break. A family spending $100 on school clothes and supplies saves $5. A family buying a $1,000 computer saves $50.

Still, some observers say retailer interest in the state's annual break is flagging. Some question who the break benefits. And reliable figures to support how much consumers save or spend because of the tax break remain elusive.

Deborah Fowler, director of the University of South Carolina's Center for Retailing, says retailers aren't that excited. "I think the first year it was very, very exciting," she said. This year, interest has been "decreasing at their stores," Fowler said.

"Not to us it hasn't," said Bryan Fenton, manager of Wal-Mart's James Island store near Charleston.

Merchants should be excited. William Fox, a University of Tennessee professor, says one study has shown merchants get 80 percent of the benefit from sales tax holidays. Retailers "did not reduce prices as much as they otherwise would have done," Fox said. "Are you in fact helping people be better off?" Fox asked as he testified before a state panel Thursday on the state's sales and other tax issues.

There's no statewide accounting to show people spend more because of the sales tax break than they would otherwise for back-to-school items. The state Revenue Department says the first year cost South Carolina $3.6 million in lost tax collections. The loss fell to $2.7 million in 2001 and was $3 million last year.

"That's really not a complete story because the sales of nonexempt stuff goes up," said Jim Hatchell, of the South Carolina Merchants Association. The exemptions cover computers, paper, clothing and a variety of other products. But Hatchell says sales also increase on nonexempt items, such as jewelry and most sporting goods.

To get people into their stores this weekend, retailers have to offer discounts, Fowler said. But they have to balance the cost of staffing with the double-digit discounts retailers have trained shoppers to look for, she said.

Danny Brazell, a spokesman for the Revenue Department, said any retailer at any time can tell their customers they'll absorb the sales tax. The retailer is still responsible for accurately reporting sales and paying the tax on nonexempt items.

S.C. stores near the Georgia line face new competition on the tax-free weekend front. Georgia launched its first back-to-school tax-free weekend Thursday. North Carolina starts its second back-to-school tax free weekend Friday, too.