You are allowed to log into some amount of Deepweb marketplaces with the only help of urls, that suggests a tricky situation : upcoming customers and vendors don’t have a possibility join the market before they will gtab an alternative URL from an previously registered customer.
Search for those at http://deeponionmarkets.com/, it posts fresh alternative links to suggested Deepweb marketplaces. You shall follow these alternative URLs to sign up at the sites.
In case that there are some troubles with an access,for example, links won’t work, you shall lie in wait and check for Dark Web marketplaces urls. Persist with it, for the reason that some of the markets may stop and launch registrations periodically, due to server load.