Upwork: This website offers a great marketplace for selling just about any professional service. You don't need a merchant account, a website of your own or anything else for that matter. All you need to do is be able to provide a high-quality service at a reasonable price. But be informed, you will have to compete with many others that are constantly bidding on open jobs.
Selling clothes you no longer wear is a quick way to make some money. Start with local consignment shops for faster cash, or use sites like ThredUp and Poshmark to find buyers. If you go the online route, be sure to take clear, well-lit photos of your pieces and research similar items to set competitive prices. Get tips on how to sell your clothing.