Darknet marketplaces promote cybercrime as these platforms enable and facilitate the trade of illegal goods and services as well as malware, exploits and stolen data through a high degree of anonymity. This is increasingly becoming a problem as it poses major challenges to law enforcement efforts and maintaining cyber security. The combination of user anonymity and the use of cryptocurrencies enables cybercriminals to carry out illegal transactions efficiently and with a low risk of detection. As a result, a dynamic ecosystem has emerged that benefits both buyers and vendors, while systematic insights into vendor behavior and the correlated market structures remain scarce. This paper analyzes the process of becoming a vendor, focusing on its complexity, the insights into sales conditions as well as their success measured in turnover, with the aim of gaining a better understanding and counteracting illicit online activities. We compare entry requirements for buyers and vendors, highlighting common features such as security measures, vendor-specific rules and the revenue model shedding light on commission structures within darknet marketplaces. Our findings also show that vendors across all product categories are able to generate multi-million dollar revenues across the marketplaces they operate as well as operated on.