Cute Casual Dresses!

There are so many things that I needed to do before hitting December. One in my lists is to buy new casual dresses for the three formal parties that we are going to attend next month. I have few casual dresses in my closet but I already wore it last year during the party. I bought a pair of black boots and a wool coat last week and I just need casual dresses.
I want the one that matches to my knee-high black boots, simple yet elegant and of course affordable. I wanted to go to the mall and shop but we are three hours away and the road is icy so I think shopping online is the best option at this moment. I am browsing for sample outfit picture wearing knee-high boots and I only found few so right now, I am still not sure what type of dresses to buy. Do you have any suggestion?