It's a vest! It's a dress! It's a vest-dress! And, it's on sale now at Shopbop for $119. Still too much? Try Forever 21's vest-dress hybrid (above right) for just $17.99.
Left: Marc by Marc Jacobs Sparkle Sateen Dress, Was $398.00 Now $119.40 at Shopbop.com
Right: Pinstripe Halter Dress, $17.99 at Forever21.com
It was pretty nice too, also in black.