New London — Spring is in the air, and so is prom.

And with a recent survey that shows that nationally, the average family spends more than $1,000 on prom night, organizers of a Prom Expo are hoping they can help curb those costs. In the Northeast, according to the survey, the cost of prom is an average of $1,900.

Mia Berube, owner of Greenlight Boutique on Bank Street, is organizing the Sunday event, which will take place from noon to 5 p.m. Sunday at the New London Lodge of Elks, 81 Washington St.

Teens will be able to buy used prom gowns, some costing up to $400 new, for $10 to $30. The expo will also include a 2 p.m. fashion show, and the first 50 prom girls through the door will receive free gift bags.

“Some of these dresses are beautiful,’’ said Berube, who has been accepting donations for weeks.

Raffle tickets will be sold for a chance to win a free gown, tuxedo rental, flowers, jewelry, pedicures and manicures, and gift certificates. Makeup and hair demos will be given. Accessories and shoes will also be for sale.

The event is free and open to all from the region. Donations will be accepted to benefit the New London High School and Science and Technology Magnet High School drug-and-alcohol-free party for the Class of 2012.