Have you heard of this awesome site?!?
Being Mormon I sometimes have a hard time finding elegant FORMAL attire for work parties, weddings, holiday events, etc. I feel like most dresses that are modest are also made out of NOT "formal" fabric--cottons, linens, etc. I need SILK and SATIN, people!
In comes RENT THE RUNWAY...
They are designer dresses that you rent ($50-$200). You pick the dress, you pick your size (they will send you a back-up size for free), and they will mail it to you in time for your special occasion.
Now, just beware, most of the dresses are NOT modest, but I have always been able to find between 15-20 dresses that ARE modest and totally appropriate for special occasions. Plus, nothing makes me feel better than knowing I'm wearing a $1000 Badgley Mischka dress that I paid $50 to rent for the weekend! haha!
so, get a free account at http://www.renttherunway.com/