Step out in style wearing this long polka-dot halter prom dress that is sold exclusively at PromGirl. A vintage style for prom, galas, and other formal events, this long special-occasion dress has an all-over polka-dot print from the sweetheart neckline to the hem. The long polka-dot formal dress has a halter bodice with sturdy shoulder straps that attach at the back of the neck, while the hip-hugging long skirt opens in a side slit before ending in an eye-catching train. A vintage style with plenty of modern details, this long polka-dot halter prom dress is a statement maker that is surprisingly affordable at under $200.