Can't locate the right dress style

I’m a guy who’s been wanting to check out this site for the past year. I was looking at the scenarios and noticed the long walk (the one where you dress in women’s clothing, are bound up, and have to venture outside into public to retrieve your key). Anyway, I’ve been searching online for that specific type of dress but haven’t found it yet. All I could find were short versions ending around the knee, not ankle-length ones. So here’s my question:

A) What is this kind of dress called? B) On average, how much do they cost online?