SOUTH PORTLAND -- By mid-morning, Tom Walsh already had new shoes for his 5-year-old daughter and 6-year-old son in hand.

It was Walsh's first back-to-school shopping foray of the season with Isa and Thomas. There was plenty more that needed to be purchased before the children start school at Wayneflete School in Portland in the first week of September.

"There will be more. Today's just the start," Walsh said Monday at the Maine Mall. "The list of needs keeps growing."

They are keeping an eye open for more shoes, clothes and "bargains we can't do without," Walsh said.

While the Walshes have only started their shopping, most Americans began their back-to-school preparations earlier this summer than in previous years, according to the International Council of Shopping Centers. A survey commissioned by the trade organization suggests that high gasoline prices and other economic worries have shoppers searching for bargains.

"Usually people shop earlier to save money. There are more sales earlier in the back-to-school shopping season," said Erin Hershkowitz, a spokeswoman for the council. "A lot of people are looking to get more value out of their purchases this year with the uncertainty of the economy, gasoline prices as high as they are."

Back-to-school shopping is getting under way earlier and earlier, with this season starting in early- to mid-July, Hershkowitz said.

The back-to-school shopping season is a distant second to the Christmas holiday season in the retail sector, but it is still an important time for merchants who rely on this time to boost sales, Hershkowitz said.

The council estimates that back-to-school shoppers will spend $38.5 billion between July and September this year, a 1 percent increase from the same period last year. U.S. households are expected to spend about $400 each on average.

In Maine, retailers are in the season following a sluggish June. Figures from Maine Revenue Services indicate general merchandise sales were down 1.6 percent from the previous year. The category includes products carried by large department and discounters, including clothing, shoes, televisions and furniture.

"You like to see something that's a little more than inflation," said Jerome Stanhope, a financial analyst in the economic research division. "You're not keeping up with inflation at these rates."

While it's not possible to know the precise reason behind the drop in sales, Stanhope said it seems that people are having to spend more on gasoline and heating costs - or at least are worried about those costs rising.

"You don't have that money to spend on restaurant meals, new shoes or school supplies," he said.

The Newcastle-based Renys chain started seeing back-to-school shoppers at the end of July, said John Reny, the company's president. He said sales at the company's 14 stores, which stretch from Wells to Ellsworth to Madison, were up in June and July and will likely be up in August as well.

Sales in those months may also have benefitted from tourists and rainy weather that kept people indoors this summer, he said.

Reny had noticed that customers are looking hard for value in their purchases, buying basic clothing items and sometimes heavy coats. He said there was increased interest in the stores' layaway program, which allows customers to pay for an item in installments without any interest charges.

"Traditionally, we've done well in bad economic times," he said. "I wouldn't be in business if I couldn't meet or beat prices of the other guys."

L.L. Bean saw a surge in sales through its catalog and at its flagship store in Freeport in late July and early August, said Carolyn Beem, a company spokeswoman.

The increase was particularly noticeable in children's products. Strong functional clothing - like jeans, khakis, sweatshirts and fleece items - as well as bookpacks and lunchboxes have been strong sales, she said.

Those kinds of purchases are in line with the research for the International Council of Shopping Centers. Hershkowitz said shoppers are looking for basics rather than trendy items that can become dated quickly.

"People are going back to basics, looking for value, looking for things they can hold onto longer," she said.

According to the International Council of Shopping Centers survey, 78.5 percent of consumers expect to finish back-to-school shopping before the end of August, up from 72.7 percent last year and 69.5 percent in 2006. About 34 percent of households had already started their shopping at the time of the survey, July 17 through July 20, and 7 percent were already finished.

Nearly 90 percent of households planned to shop at discounters, up from 49 percent in 2005.

At the Maine Mall, the window displays were showcasing autumn apparel. Despite the sunny weather Monday morning, shoppers were already busy in the stores.

Ashley Riley and Rebecca Martin, 14-year-olds who will be freshmen at Gray-New Gloucester High School, arrived soon after the mall opened. They already had several bags between them as they emerged out of PacSun.

Their shopping priorities showed that, whatever the economy, a trip to the mall can still be about getting that perfect find. So far, it was a gray T-shirt for Ashley and a black T-shirt with a glittery outline of a dove for Rebecca.

Bargain-hunting wasn't their top goal. For them, it was more important to find items that expressed their fashion selves.

"Anything we really, really need that shows out true colors," Rebecca said.