What are the best business models for charging users of a marketplace?

Marco S├ínchez has some great answers on this subject, but. I would just add a few more options that are working well at scale: Pay to respond to a bid (for service-based sites like Thumbtack). The reason Thumbtack settled on this business model is because it (a) reduces leakage – lost revenue if/when customers and suppliers interact off-site, and (b) …