After a nerve-rattling plunge, stocks in Asia, Europe and the United States managed to end the week ahead of where they started.

But not so for industrial commodities. Their prices just keep heading south — creating more worries for miners, but good news for many manufacturers and consumers. The price drops could even help depress interest rates for all sorts of borrowers.

Before considering the impacts, first check out the magnitude of the changes. These are approximate prices, compared with one year ago:

Iron-ore prices have been especially hard hit, falling to just $44.10 a ton a few days ago. In early 2011, the price was nearly $200. By week's end, prices had nudged back up to roughly $49, but they remain far below peaks.

These price collapses can help manufacturers who must purchase raw materials to make finished goods.

Here's one example: Back in June 2008, aluminum hit a high of about $3,100 a ton. Today, the price is down to almost half that. So if you are making fuselages at a Boeing plant, this cheaper aluminum may help your employer earn bigger profits — and that might make your job more secure.

For steelmakers, cheaper iron ore means lower production costs; for lighting fixture manufacturers, cheaper copper can mean higher profits, and so on. Or the savings can be passed along to consumers.

That pass-through certainly has happened with oil. AAA, the auto club, says that thanks to the dramatic drop in crude oil prices, drivers are paying an average of about for gasoline, compared with $3.64 one year ago.

And a new forecast from the International Energy Agency says oil prices will most likely fall further because the world is "massively oversupplied" with crude oil.

But for the companies that mine or pump these raw materials, the price drops have been brutal. For example, thousands of U.S. workers in northern Minnesota have lost jobs as iron ore mining operations have scaled back. Arizona's copper miners have been hit with layoffs, and oil patch workers in many states have been sent to unemployment lines.

What's the cause of the commodity price drops?

Analysts attribute most of the change to China, which just isn't building infrastructure, skyscrapers and apartments the way it had been a few years ago. The economic slowdown in China means less global demand for steel, copper and other materials used in construction.

Metal Bulletin's report on iron ore on Tuesday, a particularly bad day for prices, said: "Markets for the whole ferrous complex were in free-fall. ... The recent crash in China's stock market further aggravated fears of economic decline in the country."

But it's more than China. Europe too has been struggling to grow, and now its prospects are being clouded by the Greek debt crisis. The IEA report said crude oil is being depressed by the "financial turmoil in Greece and China."

While raw material prices don't necessarily get passed along directly to consumers, they do factor into the overall inflation picture. And these days, inflation remains extremely low worldwide, with the Organization for Economic Cooperation and Development pegging the annual consumer inflation rate at 0.6 percent.

On Thursday, while speaking with reporters in Chicago, Federal Reserve Bank of Chicago President Charles Evans said the Fed probably should delay an interest-rate increase until mid-2016 because inflation is still so low and the risks abroad are so great.

"There is a worldwide low inflation issue that no one right now is able to address with their monetary policies," he said.

In other words, the drop in commodity prices could mean a cheaper car loan for you later this year. In a world where we're all connected, everything else is connected, too.

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