Are you looking to create an exchange type platform - more likely a forex exchange? In that case you should be looking to create an exchange along with trade/matching engine. There are a few open source exchange softwares available that helps you to create order books like they do in case of Crypto currency exchanges.
If you are looking to create an Ebay clone, then there are simple woocommerce plugins that can get you started without technical overheads.
So, to me, the question isn't too clear and also I am unaware of your technical expertise - so as to provide a more proper reply.