Apple Computer Incorporated’s chief executive, Steve Jobs, introduced a lower-priced iPod music player and the least expensive Macintosh computer in the machine’s 21-year history to expand consumer sales of both products.

The iPod Shuffle uses a less-costly type of flash memory and will start at less than $100. That compares with the $249, 4-gigabyte mini with a traditional hard-disk drive that can hold 1,000 songs. The Mac Mini personal computer will sell without a monitor, keyboard or mouse starting for $499 on January 22.

Mr. Jobs, 49, is trying to court consumers turned off by Apple’s pricing and fend off rivals in the digital music market. The iPod sells for $249 to $599, while flash-based players sell for less than $200, Mr. Jobs said. The flash memory music market is five times larger than the hard-drive market in units and double the revenue, according to Merrill Lynch & Company’s Steven Milunovich.

“There’s a lot of choice with iPods,” Mr. Jobs said at the Macworld Expo in San Francisco today. “We think it’s going to make the iPod more accessible to even more people.”

Shares of Apple fell $4.40 to $64.56 in Nasdaq Stock Market composite trading. Some investors may have expected the company to report holiday quarter iPod sales of as many as 5 million units. Mr. Jobs reported 4.5 million.

“There is an iPod whisper number of 5 million units,” an analyst at Piper Jaffray Companies in Minneapolis, Gene Munster, said in an interview. “That’s why the stock is down.

“The big picture is that Apple is going after the mass market,” said Mr. Munster, who rates the stock “outperform” and doesn’t own them. “Apple is going into the mass market for the first time in both the PC market and the digital music market.”

Two versions of the iPod Shuffle were shipping as of yesterday, including a $99 model with 512 megabytes of memory that holds about 120 songs, Mr. Jobs said. A version with 1 gigabyte of memory sells for $149.

The Mac Mini gives the company, for the first time, a cost-competitive computer to rival PCs built on Microsoft Corporation’s Windows operating system. Dell Incorporated, the no. 1 PC maker, sells systems starting at $499, according to the company’s Web site.

“We want to price this Mac so that people thinking of switching will have no more excuses,” Mr. Jobs said. “It’s the cheapest computer Apple’s ever offered. It’s the most affordable Mac ever.”

Until now, Apple’s lowest-priced PC was the $799 eMac, which combines a monitor and computer into a single unit. The Mac Mini works with industry-standard keyboards and monitors, so current PC users can use their existing equipment to work with the new machine, Mr. Jobs said.

Apple could sell the Mac Mini without hurting margins to iPod owners who want an easy-to-use PC that works with the player, Mr. Milunovich told investors last week.

The company is trying to exploit euphoria around the iPod to help sell iMacs, analysts said.

“What Apple is trying to do is capitalize on this ‘halo effect,”‘ Mr. Munster said. “The person who goes into an Apple store, purchases an iPod, starts to check out the computers. I think that people who have iPods will buy the iPod Shuffle too.”

Mr. Jobs couldn’t pick a better time to woo Windows users, said UBS AG an alyst Benjamin Reitzes in New York. Microsoft’s delayed release of the next version of Windows, code-named Longhorn, until 2006 gives Apple a chance to win PC share in 2005 “given its revitalized brand due to the iPod,” he told investors earlier last week.

“Apple will ship a new version of the Mac operating system software in the first half of this year,” Mr. Jobs said. “That’s going to be long before Longhorn.”

Apple’s holiday iPod sales were more than double the 2.02 million Mr. Jobs shipped in the prior quarter. Those sales bring the tally to more than 10 million since the player was introduced in October 2001, with more than 8 million sold in calendar 2004 alone, Mr. Jobs said.

The iPod is also the fastest-growing product at Apple, accounting for 23% of the $2.35 billion in fourth-quarter sales, up from 7.1% a year earlier. Mr. Jobs is scheduled to announce the company’s results for the fiscal first quarter today.

Apple’s player is the most popular hard disk-based music player on the market, holding 83% of the market for such devices in the 12 months ended in October, according to Port Washington, N.Y.-based NPD Group.

The new iPod Shuffle uses flash memory, which stores data on semiconductors instead of drives with moving parts. Flash allows for more shock-resistant, sleeker, and less costly designs. It weighs less than an ounce and is “smaller than most packs of gum,” Mr. Jobs said.

Unlike its siblings, the iPod Shuffle lacks a screen and menu for selecting songs. Instead, the device randomly plays or shuffles through music tracks, Mr. Jobs said.