Where can I find a dress like this?

I would definitely not buy that dress! Especially if it's for something like prom. You will regret it. I bought a $600 designer dress one prom and ended up having to resale it for $50. Then the very next year I got a super cheap $99 dress from this website called lightinabox.com and got SO many compliments on it. Way more than I got with the expensive dress.

you can shop around at lightinabox.com They have tons and tons of different dresses. I've boughten several dresses from them for dances and pageants and they are super reliable. I'm always happy with what I get. They're a very trustworthy site. Plus, they will make the dress in any color you want, so you can get the lilac if you want it! Some of their dresses are super cheap and some are a little more expensive, but their steal half the price of designer dresses. You can always find a good deal on that website, they're always having sales.

Some dresses I found that were similar to the one you liked were:

Dress 1:

http://pinterest.com/pin/39688040437659468/

Dress 2:

http://www.lightinthebox.com/sheath-column-sweethe...

Dress 3:

http://www.lightinthebox.com/sheath-column-sweethe...

Dress 4:

http://www.lightinthebox.com/Sheath--Column-Sweeth...

You can look around and try to find some more you like better if those aren't close enough. Another store I would recommend is L'Patricia. I don't know if there is one where you live and they don't have an online store, but you could search for the nearest one and if it's not too far take a shot. They have hundreds of imitation designer prom dresses for under a $100. They don't look cheap or anything either. You can't tell the difference!