Unique Vintage Prom A secret source for affordable prom dresses is Unique Vintage. They revamp their site and added a new second site that's dedicated to prom! The site sells dresses that you won't find anywhere else, and the options are all really inexpensive. Best of all, Unique Vintage offers free shipping for orders over $150. Grab a friend and get your dress together to get a free delivery! Rent the Runway Ever dream of rocking a red carpet Taylor Swift look? Rent the Runway lets you rent designer gowns for totally reasonable prices! Even though you have to give the gown back, you're guaranteed to feel like a celeb on prom night. You could wear a $1,000 dress for only $100 or less! In addition, they currently have a promotion for new users - $25 off your order of $75+. Now, that's a steal! ModCloth Need something sweet, sassy, classically vintage or ultra-modern? ModCloth offers fabulous formal frocks that will let you stand out at any event. You can shop by color, price, and style. It's also the only place that offers petite to plus size dresses!