This also may not please the fashionistas
but when I've had to find dresses for parties like yours, BTD, I go to Ross. I also used to avoid the parties to avoid the hassle of buying formal/semi-formal wear.
I have picked up my LBD, my long BD, and more for under $20 each. The clothes they have are the same they sell at the other stores but reduced. And, since these dresses are 'timeless' you aren't getting last seasons dress, just paying a lot less.
But, have patience with the crowds. Everyone is looking for that perfect dress for the perfect price and a lot of them drag their crying kids with them. THAT is what I don't like. But, it can be worth it. Sort of like factory shopping {but I don't remember kids there....}
Stay focused if you decide to shop at Ross...you are on a mission, don't let the opposition sway you....
Ooo, wow, steph, that is a beautiful dress....