Here's an elegant long formal prom dress with two looks in one. This faux-wrap dress changes into an off-the-shoulder style with little effort. Just adjust the shoulder straps to drape over the upper arms, and viola, you have transformed a simple sleeveless prom dress into an alluring off-the-shoulder evening gown for a second glamorous look. In misses and plus sizes, this long formal dress has side ruching to hide the tummy, while the long skirt opens in a side slit for a sexy vibe at prom, military balls, and other black-tie events. Totally affordable, at under $150, this long formal prom dress offers two upscale looks at a budget price.