At Saks Fifth Avenue, a Carolina Herrera Italian wool jacket with an oversized portrait collar and stiff, voluminous sleeves sells for $2,190. Mass retailer H&M, meanwhile, is offering a wool and rayon jacket with a similar shape for just $39.90.

Inexpensive knockoffs of this season's high-end clothes have been showing up everywhere from Zara to Target, as they do each season. But unlike the casual jersey dresses and drapey styles of recent years, this season's more formal, couture-inspired looks, with their unusual shapes, extensive stitching and luxurious fabrics, are harder for the cheap-chic crowd to copy.

That means in some cases the difference between high-end clothes and low-end copies is clearer than it has been in years — and that's exactly what some designers had hoped for. Graeme Black, who recently stepped down as chief designer of women's wear at Ferragamo to focus on an eponymous line, says part of his goal in creating cocoon-shaped coats and jackets with draped collars and puffy sleeves for both labels was to set them apart from mass-market styles.

"When you were just applying beads and sequins to denim, the cheap stuff and the expensive stuff all looked the same," says David Wolfe, creative director for the Doneger Group, a New York retail consultancy, referring to the casual styles of previous seasons.

For consumers looking to mimic this fall's high-end looks without paying a premium, it might mean settling for some key differences.

At Kohl's, for example, one popular piece from the inaugural fall collection of the Simply Vera Vera Wang line is a bubble-skirt done in a polyester fabric. It resembles a stiff, expensive brocade but has a flatter shape than the poufy bubbles featured on designer runways.

"We felt the true bubble, which is so fabulous and so theatrical, was probably a bit too out there for our customer," says Sara Dennis, senior vice president for Simply Vera Vera Wang. Vera Wang says she intends for her Kohl's pieces to look different from runway styles: "The idea is to create items that can stand on their own."

Browsing at a Zara store in New York recently, Gillian Burkley, a 24-year-old actress, found several couture-inspired pieces she liked, including a cape-like jacket that she tried on. "It's beautiful," she said, adding that she didn't mind that it was made of a cheaper fabric.

The more formal styles, at both the high and low ends, are helping to push up sales of women's apparel. Based on sales so far this year, sales are on track to rise a predicted 4.8 percent to $100 billion in 2007 compared to 2006, according to Marshal Cohen, chief retail analyst for market researcher NPD Group. "Women's apparel is having its best year in close to a decade," says Cohen, who attributes the rise to a return to less-youthful styles.

Mass-market retailers began focusing on the new styles last winter, after high-end designers started showing their dressy, structured looks at fall runway shows in February.

Karolyn Wangstad, vice president of trend at J.C. Penney, picked up on these looks when conceptualizing the Nicole by Nicole Miller and Worthington lines. Her team focused on the garments' "dressmaker details," such as intricate shaping of the sides and backs of outfits and the puffiness of the sleeves. The result: short jackets with stiff, bell-shaped sleeves in cotton and polyester blends, ranging in price from $35 to $60.

To keep costs down, Wangstad says Penney used plastic dressmaker snaps instead of the metal snaps many high-end designers use in such pieces. The company also used fewer covered buttons than would be found on runway pieces.

Typically, the most difficult parts of an item of clothing to sew — and thus, to replicate — are sleeves, any pieces with curved shapes, collars, and detailing.

With dramatic puffy sleeves, for example, each sleeve has to have the same amount of volume or the wearer ends up looking deflated on one side. And shoddy stitching around the arm-holes can result in unsightly puckering.

Collars and ruffles, too, look best if they are completely symmetrical. And outfits that have rounded shapes such as a tulip skirt or cocoon jacket sometimes have curved seams, which can be hard to execute well, resulting in a lumpy look in some areas.

John Mincarelli, professor of fashion merchandising at the Fashion Institute of Technology in New York, recently examined a $3,165 Lanvin dress that Intermix boutique says has been one of its bestsellers this season. It features a distinct "leg-of-mutton" sleeve, which is puffy at the shoulder and tapered at the wrist. He noted that the suede-like washed-silk fabric is hefty enough to hold its shape and the stitching at the wrist, and arm-holes have been sewn so that each sleeve has retained the same amount of volume.

By comparison, a $59.90 H&M dress with similarly shaped sleeves looks "limp," he said. The dress, which features pin-tuck stitching at the upper-arm to "pouf it up" and a tapered wrist, is made of a fabric that isn't tightly woven enough or beefy enough "to hold its shape when it's being worn," he said.

Jennifer Uglialoro, spokeswoman for H&M, says the retailer's designers "interpret high-fashion looks to make them more accessible to the H&M consumer," adding: "H&M prides itself on quality stitching and detailing of the garments."