I work as a shopping service in Tokyo, so I usually don’t have the dresses in my possession unless someone sends me out to buy them (or I already own them). :)
The items advertised on my Tumblr are things I have seen for sale in shops around Tokyo, so it really depends where the dresses are. The ones from Closet Child are usually secondhand, but occasionally I have some brand new items from shopping assignments that customers dropped out of.
Basically, it’s a mixture of new and used.
I hope that answers your question. (^_^)