The Elk Rapids Historic Township Hall has served as a social and political center for 125 years.

Now the elegant brick building with the mansard roof and tall, arched windows is being transformed into an upscale resale boutique for prom-bound teenagers.

The hall will host the second annual Dress Swap and Shop from 11 a.m. to 4 p.m. Saturday. The sale is a fund-raiser for Project Graduation 2008, an Elk Rapids High School parent organization putting on this year's all-night senior party. Organizers hope it will raise about $2,000 for the party, while helping to make the cost of going to the prom more affordable.

"If you have checked the price of formal wear these days, $300 is not an unusual amount to pay for one dress," said swap sale organizer Cynthia Mayeaux of Williamsburg. "I think that along with being a fun way to raise some money, it is going to be of help to many girls in our communities."

The event works like this: Girls donate formal dresses they no longer want or sell them on consignment for a 70/30 split. Then they shop for like-new dresses -- many for under $100 and some for as little as $50 - from the hundreds displayed by size or color. The money they make from the sale of their old dresses offsets the cost of their purchases.

Last year's inaugural sale featured some 300 dresses and accessories, from short, flirty frocks and ballroom and pageant gowns to shoes and jewelry, said Deb Gamelin, who came up with the idea after attending a school-based sports equipment swap. Held in the middle school lunchroom and kitchen, it attracted girls from as far away as Kalkaska and Traverse City.

Some shopped on their own, others came in groups or with their moms, and a few came with their boyfriends, said sale volunteer Jami Gray. Her tuxedoed son, Jason, handed out discount coupons for tuxedo rentals in exchange for a free rental come prom time.

"What happens is a lot of times on spring break, girls go down to Florida or the Bahamas and look for dresses. Or they go on these buying sprees in Chicago or New York," Gamelin said. "So we wanted to have it before prom or Snowcoming, which is the winter dance."