By Matthew Davies
BBC World Service business reporter
The cash tills at any one of Wal-Mart's giant retail stores are rarely quiet.
Wal-Mart dwarfs its rivals in the retail business
Customers bought more than $284bn (£153bn) worth of goods from the world's largest retailer in the year to the end of January.
That means Wal-Mart's tills took well over $500,000 every minute of every day.
The sheer size of the company is staggering.
It employs more than 1.5 million people across the world through more than 3,600 sites in the US, and more than 1,500 sites in Mexico, Puerto Rico, Canada, Argentina, Brazil, China, South Korea, Germany and Britain.
And in just three months, it sells what its nearest US competitor, Home Depot, sells in a year.
So, what is the secret?
"We shop here because the prices are great and the service is wonderful," raves one customer at a Wal-Mart store in New Jersey.
Consumers are enthusiastic about the value for money it affords, but many observers are quick to point out what they see as Wal-Mart's substantial flaws.
Three-and-a-half years ago, current and former female Wal-Mart employees filed a massive sex discrimination class action lawsuit, charging that the company discriminates against its female employees in promotions, compensation and job assignments.
And whenever a new store is opened in the US, critics claim small businesses and local jobs are lost.
Small town roots
Wal-Mart's president and chief executive, Lee Scott, denies this.
"In the US, Wal-Mart has had unparalleled growth over the last 20 to 40 years," he says.
"If you look at it, there are more small businesses that exist in America today than there ever have in the existence of the company.
"Wal-Mart puts a Super Centre in, and who comes out by us? Different small industries, different small businesses, and they continue to do well."
Wal-Mart has its roots in a town called Bentonville, in Arkansas.
From there, the company's founder, Sam Walton, sowed the seeds that would grow into the world largest retailer and enable the Walton family to amass a fortune thought to worth around £102bn.
But when Wal-Mart comes to town, opinion in local communities can become polarised.
The company is hoping to start building a new store in Rosemead, near Los Angeles. Local resident Larry Bevington opposes the plan.
"It's not a cut-and-dried deal, and people only get stronger in their opposition to Wal-Mart," he says.
No union here
But on the other side of the divide in Rosemead, Jean Hall thinks having a Wal-Mart in her neighbourhood is a great idea.
"They provide jobs for the community, and they have a great record as far as being supportive to charities and community projects," she says.
Critics argue Wal-Mart puts smaller shops out of business
Wal-Mart is often criticised for opposing trade union activity among its employees, who are called "associates" by the company.
A group of Wal-Mart workers in Colorado are in process of trying to create a union at a store in Denver.
Ernest Duran, of the United Food and Commercial Workers Union, says efforts at collective bargaining have met opposition from Wal-Mart.
"Any time there's any mention of a union within a store they send in about 20 to 30 suits from their main office and they talk to workers day and night, and they talk them into not being represented by a union," he says.
As Wal-Mart gets bigger, it will likely attract more negative comments, says Richard Hyman, of retail analysts Verdict.
"It has to gain a greater sensitivity than it has been historically famous for," he argues.
There is an old retail saying: "The customer is always right".
So, how much does the company's perceived bad reputation concern Wal-Mart's customers in New Jersey?
"It doesn't bother me at all. People still have to eat and still have to buy stuff," says one shopper.
But another man disagrees. "I don't think much of this store and I don't think much of Wal-Mart. My wife's here exchanging a gift."