You want to look like a million bucks for that holiday bash. But your closet's as empty as your wallet. Instead of snagging a cheap outfit at the mall, try renting an upscale one online. A new crop of merchants will loan you fresh-off-the-runway dresses, luxury handbags and Oscar-worthy jewelry for a fraction of their price. New York City-based Wardrobe ( wardrobe-nyc.com ) mails couture and designer dresses by the likes of Zac Posen, Yves Saint Laurent and Chloe across the country for 15 percent of retail (usually $300 to $600 for up to four days), plus shipping. Or visit its showroom for a consult. Bagborroworsteal.com (from $6 to $265 per week, plus monthly membership from $9.95) specializes in designer handbags and jewelry. Borrowedbling.com (memberships from $29.95 per month) carries purses, jewelry and belts. Now all you need are shoes.