Prom is expensive. That’s why Khai Nguyen, owner of Koi Nails (www.koinails.com) in Ellicott City, Md., has had such success with the salon’s $30 prom package. “We have found that with all the other costs associated with prom — dress, hair, makeup, transportation, etc. — having a prom package that’s tailored to that special night at an affordable price gives them one less thing to worry about,” says Nguyen. The salon promotes the special — which includes a Signature Mani and Pedi — through its website, Facebook, and Twitter. Teens have to “like” them on Facebook to redeem the deal. “More often than not we are able to convert their family and friends into regular clients as well,” he says.