Have you tried doing a Google search for topics related to market places on the dark web?
even if you try it, I think you will never be able to find it, because google or something pertinent certainly will block that place. but you can find the black market in the deep web, I guess you've heard of it, if not, maybe you should look for its own information
First of all you need a tor client, since most of the dark places work on a .union extention. Then you also need a 'dark' mailadress
so you can't be traced.