Many of these platforms are free to list, some take a percentage of profits, and others offer direct payment upon sale. Craigslist. One of the original online marketplaces, Craigslist (Craigslist.org) , is where you can sell used things. ... 2. Facebook Marketplace. ... Amazon. ... eBay. ... OfferUp. ... Poshmark. ... Etsy. ... thredUP. More items...