I have been searching for quite awhile for a "modest" dress. I want a cute dress that I am able to wear to work but that still fits my budget. My favorite stores have always been stores like Forever 21 and H&M but most of those dresses are too short for work wear or tank top (which unless you wear it with a blazer can't be worn in a professional workplace). So I found this dress from Asos and I bought it while it was on sale. I absolutely love it.
Other quality modest dresses I like:
J. crew: here