Mercari is a commercial C-to-C marketplace that specializes in smartphones and provides a unique user experience. Anyone can easily sell items they don’t need on their smartphones. There are some problems with traditional buying and selling second-hand goods in stores, such as slow buying, limited products, and uncertain prices between buyers and sellers, because the buyer is the middle man. Buying and selling second-hand goods through online auctions also presents problems such as a complicated listing process and a time-consuming bidding process. With “Mercari”, anyone can easily buy and sell products via smartphone. It also provides convenient and affordable transportation options through cooperation with transportation companies and convenience stores. In addition, since sellers and buyers are mainly human beings, anyone can enjoy selling their junk items in exchange for money and experience the purchase as if they were looking for unique second-hand items.