ONE hundred George Washingtons hardly go far these days. It doesn't take an accountant to tell you what any clotheshorse worth her shoe collection already knows too well, especially once the shoes, as well as the jewelry and any other touches, are factored in.

But when the challenge to assemble a great outfit, head to toe and not for a penny more than $100, went out to Lauren Conrad -- the ambitious blond of "The Hills," which kicked off its third season last week, not coincidently as her new campaign for Avon appears in magazines and a signature fashion line launches on her e-commerce site -- the pop culture phenom accepted.

Not that it would be a snap. Conrad might be the architect of her own made-for-MTV life on the reality-drama series, as well as its predecessor, the still heavily rotated "Laguna Beach: The Real Orange County," which premiered a lifetime ago in 2004. But this challenge would force the 21-year-old away, far away, from the air-conditioned sanctuaries with valet parking she frequents.

"I shop just about every other day," Conrad admits, citing Bleu on La Brea Boulevard and Madison on Melrose Avenue among her haunts. "We do so much shooting, and I never know what scenes are going to make the cut. So if you're in the same outfit twice and it ends up in the same episode, it looks like you're wearing the same outfit all the time." It's the job, in other words, not a compulsion. She swears.

Nor would this challenge be as easy as dropping into the Beverly Center's Forever 21 or Steve Madden flagships, where Conrad scores her cheap-chic fixes before a night out at Hollywood celeb spots Les Deux or Winston's. "I hate ruining a pair of $500 heels when I go out dancing. It's so dark and crowded, no one even knows what you have on from the waist down."

It's obvious, in fact, that even for this clever mall babe, the challenge wouldn't so much be the budget as the destination: Santee Alley.

To the initiated, the four blocks known as "the Alley," starting at Olympic Boulevard and ending at New Alley, are the pulsating heart of downtown L.A.'s fashion district (albeit a heart with arteries clogged by the bacon-wrapped hot dogs, topped with jalapeƱos, served from carts parked everywhere).

It's all here: off-season costume jewelry, off-the-truck fast fashion from local factories, fake designer goods. It's a mad cacophony of fast-talking foreign speak, sticky smells, deafening music, rude shopkeepers, pushy hordes of customers and questionable, cheap products and even cheaper prices.

It's nirvana for wardrobe supervisors in film and theater, for fashion addicts and bargain hunters. But for others, Santee Alley might as well be the swampy fifth rung of Dante's hell.

"It's not where I'd normally come to shop," Conrad demurs, clutching a tall Red Bull in her right hand, a roll of greenbacks in her left (it's pretty much cash-only in the Alley), as we march beyond the entrance at Pico Boulevard and Maple Avenue. "I like finding bargains. But I usually like going to thrift stores like Out of the Closet, which I'm obsessed with, for party dresses from the 1950s. I'm not used to this, not this. It's a lot of counterfeits. It's a lot of cheaply made things."

But Conrad is game. If there's one reality she immediately accepted when MTV viewers and US Weekly readers embraced her as L.C., it's that some days wouldn't be a walk in the park.

Or a walk on Rodeo, either, as one stranger, a twentysomething Latino, points out in whispers, "Hey, isn't that the chica from Laguna Beach? Shouldn't she be on Rodeo?" he asks, pronouncing the storied Beverly Hills thoroughfare with the long vowels associated with cowboys.

"It's OK if she wants to shop here, no?" snaps a middle-aged mother, now standing next to him. "My daughter loves her."

Celebrity doesn't fly with the shopkeeper at a stand crammed with rows of oversized Coach bags in every pattern imaginable. The woman physically pushes us out. Yes, she watches the show. But these are fake bags. No photographs.

As we forge ahead, there is no shortage of photo-ops. Despite Conrad's comment earlier that she's rarely called out in L.A. -- "I mean, half the population here's been in their own reality show," she quips -- it appears the other half is here, thrilled to pose with her as their wives or girlfriends or moms steady their camera-phones for the scrapbook.

Inside a shop called Remember, Conrad slings a white cotton sundress over her head, the hanger resting on the nape of her neck, while she stands in front of a mirror. Around us, dozens of separates dangle off the walls up to the ceiling. A sparkly brown jacket with large, covered buttons recalls a Marni original, but is tagged $32. On a rack is a colorful sweater with a deep neckline that suggests Missoni. It's $10.

"Oh, my God, this is just like something I got at Traffic," Conrad marvels, pulling at the bottom of a shift cut from mauve and lavender striped cotton.

The shop girl dashes to find a suitable tube top to wear under the dress when Conrad deems that the lavender crochet band at the bust reveals too much. The girl returns with one in bright white and another in an even brighter grape, each $5.

Conrad graciously takes the white tube and disappears into the dressing room. Despite the terrific $20 price tag, the white dress doesn't fit well across the chest. The lavender is a possibility.