HUNDREDS of pairs of flip-flops line the three walls - and one tree - at the new Flip Flop Shops in the Plaza at King of Prussia Mall.

The 650-square-foot boutique opened in early April across from JCPenney. The store sells flip-flops with rhinestones. It sells flip-flops with hemp straps and flip-flops with 3-inch wedge heels. It sells sparkly flip-flops, recycled flip-flops, neon, leopard-print, rainbow, floral, metallic and plenty of plain flops, especially for men.

There are covered-top flip-flops. There are lace-up suede flip-flops (which neither flip nor flop). There are thongs whose rubber soles double as bottle openers, a/k/a "church keys." Some styles sell for $19. Others cost $108. Most fall in the $25-$50 range.

Lori Kalinovich, who owns the local franchise with her husband, James, pointed to a pair of $34 Sanuks with turquoise beads. "You could wear these with a black dress on a summer night," she said. "It's not your typical rubber flip-flop from years ago."

It's also not your typical suburban mall store. In fact, the first thing you notice when you enter the Flip Flop Shop isn't flip-flops. It's fragrance.

Beach-y and coconut-y, the top-secret pumped-in scent smells a little like sunscreen and a lot like Mr. Zog's Sex Wax, a product that surfers have long used to keep their boards sticky.

Look around, and you'll notice more unsubtle shore references. Displays backlit with photos of water scenes. Shining signs with the logos of upscale beach-bum sandal brands Rainbow, Quiksilver, Cobian, Roxy and Reef. Skateboarding and surfing videos playing on a TV over the register. Wood planks on the shop's façade that conjure a boardwalk.

"The music, the scent - it's all about the lifestyle," said Kalinovich, a New Hope resident and mother of three. "It's about freeing your toes."

"Free your toes," is one of Flip Flop Shops' trademarked expressions.

Another trademarked expression: "Toes exposed."

Company president Brian Curin explained that the official slogans and island atmosphere reinforce the store's philosophy. He said it's about, "embracing the casual lifestyle, whether it's in the White House, or Kenny Chesney's 'No Shoes Nation.' "

Curin described the high-end yet laid-back shoes sold in his stores as "premium products that are more acceptable in the workplace or country club."

Despite flack from fashion policers who came out in full force in 2005 when members of Northwestern University's women's lacrosse team wore flops to meet President George W. Bush at the White House, the trend seems to be building.

Curin said that flip-flops were a "$20 billion industry, compared to the $18 million athletic-shoe industry."

Jeff Espersen, head of footwear at Zappos.com, confirmed the flip-flop phenomenon. Espersen said that Zappos carries "over 1,000 variations . . . from brands like Havaianas to Alexander McQueen, so there's a price point to fit any budget." (The budget for a pair of McQueens? A cool $672-$795.)

Those born-in-Brazil Havaianas (a favorite of supermodel Gisele), come closer to the $20-$30 range, and are more typical of the merch at Flip Flop Shops. Such pricing seems to be working out.

Curin said that 80 shops operate throughout the U.S., Canada, the Caribbean, Hawaii and Guam. He said that 114 additional shops will be opening soon.

One is scheduled to debut this summer in Manhattan, which, as we all know, is always a step behind Philly when it comes to casual fashion.

The Kalinoviches are looking for a space in Cherry Hill for their second franchise.

Of the 2,000-some pairs in her stock, Lori Kalinovich's preferred flops are OluKai, a designer that Curin called "the Mercedes of the sandal industry." (Some OluKai Italian leather thongs can cost upward of $100.)

But you're getting what you pay for, the Flip Flop franchise owner pointed out. With thick soles, arch support, a heel cup and hand-stitched Italian leather, OluKais, said Kalinovich, "would be great for a night out, dinner out, the movies or maybe shopping."

On Twitter: @LaMcCutch