An online store where you can buy and sell your items, Twice is perfect. Twice has a website and an app where you can buy and sell whatever you want. Let's start with selling since I just sold some stuff to them!
Sellin your clothes is easy as a pie. Well I don't know how to make a pie but it's a catchphrase so yeah.
Anyways what you do is clean out your closet for all those clothes that you feel are outdated for you and not just that but handbags and shoes and other things I think. You check to see what brands are accepted and follow the rules which are below: 
After using the ABC's you can send your items in by requesting a prepaid shipping label or request a selling kit which will come in the mail. Send your items to the warehouse and they will give you an offer for the items. You may request it in different payment methods: check, pay pal, store credit, and something else which I forgot. Now let's go to the buying.
Twice has both women's and men's stuff. You can buy clothing and handbags and I don't know about the men's since I haven't check it out yet. In the women's section though, you can buy skirts, pants, jeans, handbags, shoes, and tops. They also have a clearance section which is the best because I can look for a nice sale while staying at home and not going to the store. Another thing is that they have really good brands such as express, gap, style & co, and many others. Basically it's like an online thrift store, well that's how I'll explain it, that's super unique, amazing, and just everything!!