Poshmark is an iPhone application which allows you to sell or buy things from people. I had good experiences with this app and I was able to sell a few items. That being said, you are also able to find great deals on this app. (Beware, this app is very addicting. I am an example.)I think this is good for you if you are looking to clean out your closet and to sell your cosmetics. You would be surprised to see what types of stuff people are selling.
you can visit my closet on this app by searching my name "oliviachung". (You will need to go to "Feed" and select the search engine under "People" to find a person)
Another option is check out the site on your computer, but some of the functions do not work on the computer. This is my link -> https://poshmark.com/closet/oliviachung
Come check it out and show your support please :)
If you decided to make your own closet please stop by and let me know it is you, I would love to see your closet and see what goodies you have!
A few things I would like to inform you though. First, people like do bargain there. So, if you are the type of person who do not like to negotiate you might not like this app. Second, I would stay away from trading because you don't know if you can trust the other person to ship their item. If he/she has a good reputation, that is a different story. Third, replica items do exist on this app. It is like eBay in a way, so I suggest you to do your research and ask for additional pictures.
One thing I do like about Poshmark is that they will go out of their way to protect their buyers, and I speak from my personal experience. I purchased a Prada bag which was claimed as an authentic, but when I got it I definitely know it was a replica. Thankfully, Poshmark stand by their policys and helped me to get my money back.