Demarkets.io A community run website that broadcasts live the active listings of Particl's P2P privacy centric marketplace is a great option.Below is statistics section of site showing the listing growth as a graph https://www.demarkets.io/stats
Active listings https://www.demarkets.io/particl/explorer
Here you find an article detailing one of the numerous features coming to particl blockchain soon, private marketplace and store creation, where any user can either create an entire marketplace for buyers and sellers to interact or a private store where customers can access his products and services, this is done by sharing the public key. On creation of store or marketplace a private and public key will be created for this purpose https://particl.news/the-open-marketplace-and-the-road-to-mainstream-adoption-870ced49677b
But if you do not like to wait and would like to test out private market creation for yourself then you may use this guide to do so https://www.demarkets.io/news/create-markets
yet another feature coming soon to particl "Decentralized advertisements"
Private market/store creation
Particl was launched in 2017 as a non-ICO and non for profit organization it is an open-source and decentralized privacy platform built on the blockchain specifically designed to work with any cryptocurrency. It allows decentralized applications (Dapps) of all sorts to be built within a secure, highly-scalable environment and be integrated directly into Particl’s flagship Desktop client in true P2P fashion but still capable of delivering mobile solutions.
Particl's mission is to foster a new decentralized, private and democratic economy supported by its platform and native currency (PART). All the fees generated by the platform are paid to the PART coin holders who are securing the network.
https://particl.io/about-us/