DOUGLAS, Ariz. (AP) _ It's a typical day on International Avenue. Hundreds stream through the port of entry from Agua Prieta, Sonora, bound for Wal-Mart and other stores. Many more drive through; nearly all cars parked at larger stores have Mexican plates.

The shoppers include Angela Maria Ruiz, a housewife whose husband owns a small tire business in Agua Prieta. Like other Mexican citizens who routinely shop across the border, she finds the goods, the selection and the prices for many items better here.

The daily flow north is an economic engine for border cities such as Douglas, a once-thriving copper town that today has no major industry for its 15,000 residents except for two prisons and a large Border Patrol presence.

The Safeway and Bashas' supermarkets shuttle Mexican customers in school buses from neighboring Agua Prieta, a city of 100,000. Many businesses cater principally to Agua Prieta residents.

Here on International Avenue, merchants and shoppers like Ruiz grimace when asked about U.S. plans to charge Mexican shoppers $45 for new laser visa cards. Merchants worry that many Agua Prieta residents can't afford the fee; many Mexican shoppers say they can't or won't pay it.

``I like American products better, especially at Safeway or Wal-Mart,'' Ruiz said. ``But don't forget, Douglas needs us as much as we need Douglas.''

She said she might not be able to afford to keep shopping here if, as planned, the United States starts requiring some 5 million Mexicans now holding free border-crossing cards to pay for the new laser cards, which are to include the cardholder's fingerprints and a photograph. Authorities say the old cards often were misused and that the new cards will speed travel across the border.

The visa cards were to be required as of Oct. 1, 1999, as part of a 1996 immigration law, but legislation moving in Congress could change that.

On July 23 the Senate approved a measure by Sen. Jon Kyl, R-Ariz., to delay implementing the cards for five years. Rep. Jim Kolbe, R-Ariz., who represents the area, is pursuing similar legislation in the House.

For now, most of those shopping in Douglas have a free card allowing Mexicans living near the United States to travel within 25 miles of the border for up to 72 hours. Those cards were issued by the Immigration and Naturalization Service, which also provided the cards for Canadians near northern border communities.

Those without border cards must now apply at a State Department consular office for the laser visa cards and pay the $45 fee. The cards aren't being issued yet, so applicants now get a stamp on their passports permitting the 25-mile, 72-minute limit.

The question at this point is when current border card holders will have to follow suit and what impact that would have on border cities.

Douglas Mayor Ray Borane said the laser visa cards and fee are an example of Congress failing to recognize the way things work along the border.

``The people who can't afford $45 shop in Douglas,'' Borane said. ``Those who can afford it go to Tucson,'' a city 100 miles to the northwest with large shopping malls.

Pete Monarez, manager of the Wal-Mart store near the border, said the fee would hurt business.

``I think it's the charge that they couldn't afford,'' Monarez said. ``If they can come up with a payment plan of some kind, maybe that would help them.''

Mexican Consul Ecce Iei Mendoza said U.S. officials offer plenty of justification for the new cards. ``But being on the other side, that is affected, we could wish that it wouldn't hurt so much,'' he said.

Bill Bourland, who specializes in commerce with Mexico for the city of Tucson's economic development office, said real costs to Mexicans are likely to exceed $100 per person.

The costs would include the Mexican passports, never required before; travel to the limited number of American consular locations to fill out the applications and even long-distance telephone calls to schedule appointments, he said. For example, there is no full-time U.S. consular office in Agua Prieta, and many seeking the cards are expected to have to travel offices in Hermosillo or Nogales, both more than 100 miles away.

``That's really quite a substantial amount of money,'' he said. ``Take a family with three or four kids, that's going to make the cost really prohibitive.''

Clarissa Ochoa, who came over from Agua Prieta to shop at the Safeway, said she wants to continue shopping in Douglas.

``I come here to take advantage of the store sales, like milk, meat, chicken, potatoes _ goods that we can get cheaper and better here,'' she said. ``I think most people will try to come and shop in Douglas as long as they can.

``I hope the United States doesn't make it any harder for us to come here.''