If you think all those thousands of free or low-cost iPhone apps that developers are frantically banging out are being created merely for goodwill or enjoyment, think again. As much as any other gewgaw or gimmick companies offer there is a plan that explains the madness, and it's mostly about marketing.

When Stanley Works, the famous maker of hand and power tools, developed its iPhone app, it did so with the idea of introducing the venerable brand to a new generation of consumers, the New York Times reports. Some 400,000 downloads later, the company christened the effort a success, even without knowing whether the app resulted in the single sale of a new hammer or saw.

So why do it? "It was low-risk experiment," a Stanley Works spokesman told the Times. Such experimentation has led to a bevy of new apps from every kind of business. And just as popularity leads to higher pay for up-and-coming celebrities, so too are app geeks enjoying a sizeable increase in the amount paid to create ingenious new apps.

The cost to build a simple app has climbed to about $40,000 or more from about $5,000 eight months ago, the Times says.

Part of what makes apps an impressive marketing tool is those who download them are vested consumers, keen on gaining and sharing the information contained in the technology.

"Apps have a huge advantage," Carl Howe, a mobile market analyst for the Yankee Group, told the Times. "You had to take a step to get it; you are already half sold."

Apps give companies such as credit-card issuer MasterCard, which offers an ATM locator app, the ability to sell other services to a captured audience.

Not only are apps becoming more numerous, they're also becoming more savvy. Apps, such as Sit or Squat, created sponsored by the makers of Charmin toilet paper that helps iPhone users find the nearest clean public restroom, were among the first novelty apps developed. But their use is fleeting, played with a few times, shown off in a bar and then little used, the Times says.

The best apps these days are ones that involve some real utility and are used repeatedly. It's a nod to the many cell-phone users who don't want to feel they are merely tools for companies' marketing campaigns.

A growing challenge for app developers is creating apps beyond those just for iPhone, since no single type of phone has a large enough following to attract many national brands. That means not only creating an app for iPhones, but for BlackBerries and those that run on Google's Android operating system, too.